Enum that contains the following elements:
Enum that contains JerryScript API value types:
Possible types of an error:
There is also a special value JERRY_ERROR_NONE which is not an error type this value can only be returned by the jerry_get_error_type.
Possible compile time enabled feature types:
Option bits for jerry_parse and jerry_parse_function functions:
Set garbage collection operational mode
The difference between JERRY_GC_SEVERITY_LOW and JERRY_GC_SEVERITY_HIGH is that the former keeps memory allocated for performance improvements such as property hash tables for large objects. The latter frees all possible memory blocks but the performance may drop after the garbage collection.
Flags for jerry_generate_snapshot and jerry_generate_function_snapshot functions:
Generate static snapshots Snapshots contain literal pools, and these literal pools contain references to constant literals (strings, numbers, etc.). When a snapshot is executed, these literals are converted to jerry values and the literal pool entries are changed to their corresponding jerry value. To support this conversion, the literals and literal pools are copied into RAM even if the JERRY_SNAPSHOT_EXEC_COPY_DATA option is passed to jerry_exec_snapshot. This non-negligible memory consumption can be avoided by using static snapshots. The literals of these snapshots are limited to magic strings and 28 bit signed integers, so their constant pools do not need to be loaded into the memory. Hence these snapshots can be executed from ROM.
Important note: The jerry_exec_snapshot function rejects static snaphots unless the JERRY_SNAPSHOT_EXEC_ALLOW_STATIC option bit is set. The caller must also ensure that the same magic strings are set by jerry_register_magic_strings when the snapshot is generated and executed. Furthermore the JERRY_SNAPSHOT_EXEC_COPY_DATA option is not allowed.
Flags for jerry_exec_snapshot and jerry_load_function_snapshot functions:
Copy snapshot data into memory
By default the snapshot buffer is expected to be present in memory until jerry_cleanup is called. For example static const buffers compiled into the application binary satisfy this requirement.
If the snapshot buffer is freed after jerry_exec_snapshot is called the JERRY_SNAPSHOT_EXEC_COPY_DATA must be passed to copy the necessary parts of the snapshot buffer into memory.
The JERRY_SNAPSHOT_EXEC_COPY_DATA option is not allowed for static snapshots.
Summary
Jerry's char value
Prototype
typedef uint8_t jerry_char_t;
Summary
Jerry's size
Prototype
typedef uint32_t jerry_size_t;
Summary
Jerry's length
Prototype
typedef uint32_t jerry_length_t;
Summary
JerryScript value can be a boolean, number, null, object, string or undefined. The value has an error flag, that indicates whether is an error or not. Every type has an error flag not only objects. The error flag should be cleared before the value is passed as an argument, otherwise it can lead to a type error. The error objects created by API functions has the error flag set.
Prototype
typedef uint32_t jerry_value_t;
Summary
Structure that defines how a context data item will be initialized and deinitialized. JerryScript zeroes out the memory for the item by default, and if the init_cb field is not NULL, it will be called with the pointer to the memory as an additional custom initializer. The deinit_cb (if non-NULL) is called during a call to jerry_cleanup () to run any custom deinitialization before the VM has been fully cleaned up. The finalize_cb (if non-NULL) is also called during a call to jerry_cleanup () to run any custom deinitialization after the VM has been fully cleaned up.
Prototype
typedef struct { /** * Callback responsible for initializing a context item, or NULL to zero out the memory. This is called lazily, the * first time jerry_get_context_data () is called with this manager. * * @param [in] data The buffer that JerryScript allocated for the manager. The buffer is zeroed out. The size is * determined by the bytes_needed field. The buffer is kept alive until jerry_cleanup () is called. */ void (*init_cb) (void *data); /** * Callback responsible for deinitializing a context item, or NULL. This is called as part of jerry_cleanup (), * right *before* the VM has been cleaned up. This is a good place to release strong references to jerry_value_t's * that the manager may be holding. * Note: because the VM has not been fully cleaned up yet, jerry_object_native_info_t free_cb's can still get called * *after* all deinit_cb's have been run. See finalize_cb for a callback that is guaranteed to run *after* all * free_cb's have been run. * * @param [in] data The buffer that JerryScript allocated for the manager. */ void (*deinit_cb) (void *data); /** * Callback responsible for finalizing a context item, or NULL. This is called as part of jerry_cleanup (), * right *after* the VM has been cleaned up and destroyed and jerry_... APIs cannot be called any more. At this point, * all values in the VM have been cleaned up. This is a good place to clean up native state that can only be cleaned * up at the very end when there are no more VM values around that may need to access that state. * * @param [in] data The buffer that JerryScript allocated for the manager. After returning from this callback, * the data pointer may no longer be used. */ void (*finalize_cb) (void *data); /** * Number of bytes to allocate for this manager. This is the size of the buffer that JerryScript will allocate on * behalf of the manager. The pointer to this buffer is passed into init_cb, deinit_cb and finalize_cb. It is also * returned from the jerry_get_context_data () API. */ size_t bytes_needed; } jerry_context_data_manager_t;
Summary
Function type for allocating buffer for JerryScript context.
Prototype
typedef void *(*jerry_context_alloc_t) (size_t size, void *cb_data_p);
size - allocation sizecb_data_p - pointer to user dataSummary
An opaque declaration of the JerryScript context structure.
Prototype
typedef struct jerry_context_t jerry_context_t;
Summary
Description of ECMA property descriptor
Prototype
typedef struct { /** Is [[Value]] defined? */ bool is_value_defined; /** Is [[Get]] defined? */ bool is_get_defined; /** Is [[Set]] defined? */ bool is_set_defined; /** Is [[Writable]] defined? */ bool is_writable_defined; /** [[Writable]] */ bool is_writable; /** Is [[Enumerable]] defined? */ bool is_enumerable_defined; /** [[Enumerable]] */ bool is_enumerable; /** Is [[Configurable]] defined? */ bool is_configurable_defined; /** [[Configurable]] */ bool is_configurable; /** [[Value]] */ jerry_value_t value; /** [[Get]] */ jerry_value_t getter; /** [[Set]] */ jerry_value_t setter; } jerry_property_descriptor_t;
summary
Description of JerryScript heap memory stats. It is for memory profiling.
Prototype
typedef struct { size_t version /**< the version of the stats struct */ size_t size; /**< heap total size */ size_t allocated_bytes; /**< currently allocated bytes */ size_t peak_allocated_bytes; /**< peak allocated bytes */ size_t reserved[4]; /**< padding for future extensions */ } jerry_heap_stats_t;
Summary
Type of an external function handler
Prototype
typedef jerry_value_t (*jerry_external_handler_t) (const jerry_value_t function_obj, const jerry_value_t this_val, const jerry_value_t args_p[], const jerry_length_t args_count);
Summary
Native free callback of an object. It is used in jerry_object_native_info_t.
Prototype
typedef void (*jerry_object_native_free_callback_t) (void *native_p);
Summary
The type information of the native pointer. It includes the free callback that will be called when associated JavaScript object is garbage collected. It can be left NULL in case it is not needed.
Typically, one would create a static const jerry_object_native_info_t for each distinct C type for which a pointer is used with jerry_set_object_native_pointer () and jerry_get_object_native_pointer (). This way, each const jerry_object_native_info_t * pointer address value itself uniquely identifies the C type of the native pointer.
See jerry_get_object_native_pointer for a best-practice code example.
Prototype
typedef struct { jerry_object_native_free_callback_t free_cb; } jerry_object_native_info_t;
See also
Summary
Function type applied for each data property of an object
Prototype
typedef bool (*jerry_object_property_foreach_t) (const jerry_value_t property_name, const jerry_value_t property_value, void *user_data_p);
Summary
Function type applied for each object in the engine
Prototype
typedef bool (*jerry_objects_foreach_t) (const jerry_value_t object, void *user_data_p);
Summary
Function type applied for each matching object in the engine
Prototype
typedef bool (*jerry_objects_foreach_by_native_info_t) (const jerry_value_t object, void *object_data_p, void *user_data_p);
Summary
Callback which tells whether the ECMAScript execution should be stopped. If it returns with undefined value the ECMAScript execution continues. Otherwise the result is thrown by the engine (if the error flag is not set for the returned value the engine automatically sets it). The callback function might be called again even if it threw an error. In this case the function must throw the same error again.
Prototype
typedef jerry_value_t (*jerry_vm_exec_stop_callback_t) (void *user_p);
See also
Enum which describes the TypedArray types. Possible values:
API functions can return the JERRY_TYPEDARRAY_INVALID value if the TypedArray support is not in the engine.
Summary
Initializes the JerryScript engine, making it possible to run JavaScript code and perform operations on JavaScript values.
Prototype
void jerry_init (jerry_init_flag_t flags)
flags - combination of various engine configuration flags:
JERRY_INIT_EMPTY - no flags, just initialize in default configuration.JERRY_INIT_SHOW_OPCODES - print compiled byte-code.JERRY_INIT_SHOW_REGEXP_OPCODES - print compiled regexp byte-code.JERRY_INIT_MEM_STATS - dump memory statistics.JERRY_INIT_MEM_STATS_SEPARATE - dump memory statistics and reset peak values after parse.JERRY_INIT_DEBUGGER - deprecated, an unused placeholder nowExample
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_SHOW_OPCODES | JERRY_INIT_SHOW_REGEXP_OPCODES); // ... jerry_cleanup (); }
See also
Summary
Finish JavaScript engine execution, freeing memory and JavaScript values.
Note: JavaScript values, received from engine, will be inaccessible after the cleanup.
Prototype
void jerry_cleanup (void);
See also
Summary
Retrieve a pointer to the item stored within the current context by the given manager.
Note: Since internally the pointer to a manager's context data item is linked to the next such pointer in a linked list, it is inadvisable to invoke too many different managers, because doing so will increase the time it takes to retrieve a manager's context data item, degrading performance. For example, try to keep the number of managers below five.
Prototype
void * jerry_get_context_data (const jerry_context_data_manager *manager_p);
manager_p: the manager of this context data item.manager_p when jerry_get_context_data () was first called, or a new item created by manager_p, which will be stored for future identical calls to jerry_get_context_data (), and which will be deinitialized using the deinit_cb callback provided by manager_p when the context will be destroyed.Example
#include "jerryscript.h" typedef struct { int my_data1; double my_data2; char *my_data3; } my_context_data_t; /* Define how context items will be initialized. */ static void my_context_data_new (void *user_data_p) { my_context_data_t *my_data_p = (my_context_data_t *) user_data_p; /* * Initialize my_data_p. JerryScript will store it on the current context and return it whenever * jerry_get_context_data () is called with a pointer to my_manager as defined below. */ } /* Define how context items will be deinitialized */ static void my_context_data_free (void *user_data_p) { my_context_data_t *my_data_p = ((my_context_data_t *) user_data_p); /* Perform any necessary cleanup on my_data. JerryScript will free the pointer after this function completes. */ } /* Wrap the creation and destruction functions into a manager */ static const jerry_context_data_manager_t my_manager = { .init_cb = my_context_data_new, .deinit_cb = my_context_data_free, .bytes_needed = sizeof (my_context_data_t) }; /* * Then, in some function in your code, you can retrieve an item of type my_context_data_t from the currently active * context such that JerryScript will create and store such an item if one was not previously created */ static void someplace_in_the_code (void) { my_context_data_t *my_data = (my_context_data_t *) jerry_get_context_data (&my_manager); /* Perform useful things using the data found in my_data */ }
Summary
Registers an external magic string array.
Note: The strings in the array must be sorted by size at first, then lexicographically.
Prototype
void jerry_register_magic_strings (const jerry_char_t * const *ex_str_items_p, uint32_t count, const jerry_length_t *str_lengths_p);
ex_str_items_p - character arrays, representing external magic strings' contentscount - number of the stringsstr_lengths_p - lengths of the stringsExample
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); // must be static, because 'jerry_register_magic_strings' does not copy // the items must be sorted by size at first, then lexicographically static const jerry_char_t * const magic_string_items[] = { (const jerry_char_t *) "magicstring1", (const jerry_char_t *) "magicstring2", (const jerry_char_t *) "magicstring3" }; uint32_t num_magic_string_items = (uint32_t) (sizeof (magic_string_items) / sizeof (jerry_char_t *)); // must be static, because 'jerry_register_magic_strings' does not copy static const jerry_length_t magic_string_lengths[] = { 12, 12, 12 }; jerry_register_magic_strings (magic_string_items, num_magic_string_items, magic_string_lengths); }
See also
Summary
Get heap memory stats.
Prototype
bool jerry_get_memory_stats (jerry_heap_stats_t *out_stats_p);
out_stats_p - out parameter, that provides the heap statistics.Example
jerry_heap_stats_t stats = {0}; bool get_stats_ret = jerry_get_memory_stats (&stats);
See also
Summary
Performs garbage collection.
Prototype
void jerry_gc (jerry_gc_mode_t mode);
mode - operational mode, see jerry_gc_mode_tExample
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); jerry_value_t object_value = jerry_create_object (); jerry_release_value (object_value); jerry_gc (JERRY_GC_SEVERITY_LOW); jerry_cleanup (); }
See also
Functions to parse and run JavaScript source code.
Summary
The simplest way to run JavaScript.
Prototype
bool jerry_run_simple (const jerry_char_t *script_source_p, size_t script_source_size, jerry_init_flag_t flags);
script_source_p - source code, it must be a valid utf8 string.script_source_size - size of source code buffer, in bytes.jerry_init_flag_t - combination of various engine configuration flagsExample
#include "jerryscript.h" int main (void) { const jerry_char_t script[] = "print ('Hello, World!');"; jerry_run_simple (script, sizeof (script) - 1, JERRY_INIT_EMPTY); }
See also
Summary
Parse script and construct an EcmaScript function. The lexical environment is set to the global lexical environment. The resource name can be used by debugging systems to provide line / backtrace info.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_parse (const jerry_char_t *resource_name_p, /**< resource name (usually a file name) */ size_t resource_name_length, /**< length of resource name */ const jerry_char_t *source_p, size_t source_size, uint32_t parse_opts);
resource_name_p - resource name, usually a file name (must be a valid UTF8 string).resource_name_length - size of the resource name, in bytes.source_p - string, containing source code to parse (must be a valid UTF8 string).source_size - size of the string, in bytes.parse_opts - any combination of jerry_parse_opts_t flags.Example
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); const jerry_char_t script[] = "print ('Hello, World!');"; jerry_value_t parsed_code = jerry_parse (NULL, 0, script, sizeof (script) - 1, JERRY_PARSE_NO_OPTS); jerry_release_value (parsed_code); jerry_cleanup (); }
See also
Summary
Parse function source code and construct an ECMAScript function. The function arguments and function body are passed as separated arguments. The lexical environment is set to the global lexical environment. The resource name (usually a file name) is also passed to this function which is used by the debugger to find the source code.
Note: The returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_parse_function (const jerry_char_t *resource_name_p, /**< resource name (usually a file name) */ size_t resource_name_length, /**< length of resource name */ const jerry_char_t *arg_list_p, /**< script source */ size_t arg_list_size, /**< script source size */ const jerry_char_t *source_p, /**< script source */ size_t source_size, /**< script source size */ uint32_t parse_opts) /**< strict mode */
resource_name_p - resource name, usually a file name (must be a valid UTF8 string).resource_name_length - size of the resource name, in bytes.arg_list_p - argument list of the function (must be a valid UTF8 string).arg_list_size - size of the argument list, in bytes.source_p - string, containing source code to parse (must be a valid UTF8 string).source_size - size of the string, in bytes.parse_opts - any combination of jerry_parse_opts_t flags.Summary
Run an EcmaScript function created by jerry_parse.
Note: The code should be previously parsed with jerry_parse.
Prototype
jerry_value_t jerry_run (const jerry_value_t func_val);
func_val - function to runExample
#include "jerryscript.h" int main (void) { const jerry_char_t script[] = "print ('Hello, World!');"; /* Initialize engine */ jerry_init (JERRY_INIT_EMPTY); /* Setup Global scope code */ jerry_value_t parsed_code = jerry_parse (NULL, 0, script, sizeof (script) - 1, JERRY_PARSE_NO_OPTS); if (!jerry_value_is_error (parsed_code)) { /* Execute the parsed source code in the Global scope */ jerry_value_t ret_value = jerry_run (parsed_code); /* Returned value must be freed */ jerry_release_value (ret_value); } /* Parsed source code must be freed */ jerry_release_value (parsed_code); /* Cleanup engine */ jerry_cleanup (); }
See also
Summary
Perform JavaScript eval.
Prototype
jerry_value_t jerry_eval (const jerry_char_t *source_p, size_t source_size, uint32_t parse_opts);
source_p - source code to evaluate, it must be a valid utf8 string.source_size - length of the source codeparse_opts - any combination of jerry_parse_opts_t flags.Example
{ jerry_value_t ret_val = jerry_eval (str_to_eval, strlen (str_to_eval), JERRY_PARSE_NO_OPTS); }
See also
Summary
Run enqueued Promise jobs until the first thrown error or until all get executed.
Prototype
jerry_value_t jerry_run_all_enqueued_jobs (void)
Example
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); const jerry_char_t script[] = "new Promise(function(f,r) { f('Hello, World!'); }).then(function(x) { print(x); });"; jerry_value_t parsed_code = jerry_parse (NULL, 0, script, sizeof (script) - 1, JERRY_PARSE_NO_OPTS); jerry_value_t script_value = jerry_run (parsed_code); jerry_value_t job_value = jerry_run_all_enqueued_jobs (); jerry_release_value (job_value); jerry_release_value (script_value); jerry_release_value (parsed_code); jerry_cleanup (); }
Summary
Get the Global object.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_get_global_object (void);
Example
{ jerry_value_t glob_obj_val = jerry_get_global_object (); ... // Do something with global object, ex: add properties jerry_release_value (glob_obj_val); }
See also
Functions to check the type of an API value (jerry_value_t).
Summary
Returns whether the given jerry_value_t has the error and abort value set.
Prototype
bool jerry_value_is_abort (const jerry_value_t value);
value - api valuejerry_value_t has the error and abort value setExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_abort (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is an array.
Prototype
bool jerry_value_is_array (const jerry_value_t value)
value - api valuejerry_value_t is an arrayExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_array (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is an ArrayBuffer object.
Prototype
bool jerry_value_is_arraybuffer (const jerry_value_t value)
value - api valuejerry_value_t is an ArrayBuffer object.Example
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_arraybuffer (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is a boolean value.
Prototype
bool jerry_value_is_boolean (const jerry_value_t value)
value - api valuejerry_value_t is a boolean valueExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_boolean (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is a constructor function.
Prototype
bool jerry_value_is_constructor (const jerry_value_t value)
value - api valuejerry_value_t is a constructorExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_constructor (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is error value.
Prototype
bool jerry_value_is_error (const jerry_value_t value);
value - api valuejerry_value_t is error value.Example
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_error (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is a function.
Prototype
bool jerry_value_is_function (const jerry_value_t value)
value - api valuejerry_value_t is a functionExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_function (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is a number.
Prototype
bool jerry_value_is_function (const jerry_value_t value)
value - api valuejerry_value_t is a numberExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_number (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is a null value.
Prototype
bool jerry_value_is_null (const jerry_value_t value)
value - api valuejerry_value_t is a nullExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_null (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is an object value.
Prototype
bool jerry_value_is_object (const jerry_value_t value)
value - api valuejerry_value_t is an objectExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_object (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is a promise value.
Note: This API depends on the ES2015-subset profile.
Prototype
bool jerry_value_is_promise (const jerry_value_t value)
value - api valuejerry_value_t is a promiseExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_promise (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is a string value.
Prototype
bool jerry_value_is_string (const jerry_value_t value)
value - api valuejerry_value_t is a stringExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_string (value)) { ... } jerry_release_value (value); }
See also
Summary
Checks whether the given jerry_value_t is a TypedArray object or not.
Prototype
bool jerry_value_is_typedarray (const jerry_value_t value)
value - object to checkjerry_value_t is a TypedArray object.Example
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_typedarray (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns whether the given jerry_value_t is an undefined value.
Prototype
bool jerry_value_is_undefined (const jerry_value_t value)
value - api valuejerry_value_t is an undefined valueExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_undefined (value)) { ... } jerry_release_value (value); }
See also
Summary
Returns the JavaScript type for a given value as a jerry_type_t enum value.
This is a similar operation to the 'typeof' operator in the standard with an exception that the 'null' value has its own enum value.
Prototype
jerry_type_t jerry_value_get_type (const jerry_value_t value);
Example
{ jerry_value_t number = jerry_create_number (3.3); jerry_type_t type_info = jerry_value_get_type (number); if (type_info == JERRY_TYPE_NUMBER) { ... } jerry_value_release (number); }
See also
Summary
Returns whether the specified compile time feature is enabled.
Prototype
bool jerry_is_feature_enabled (const jerry_feature_t feature);
feature - jerry featurejerry_feature_t is enabledExample
{ ... jerry_feature_t feature = JERRY_FEATURE_SNAPSHOT_SAVE; if (jerry_is_feature_enabled (feature)) { ... } }
Summary
Create (api) abort from a value.
This function creates an API abort value from an API value. The second argument defines whether the input value must be released or not. If it is set to true, then a jerry_release_value function will be called for the first argument, so the api value won't be available after the call of jerry_create_abort_from_value. The second argument should be false if both value and created abort value are needed.
Prototype
jerry_value_t jerry_create_abort_from_value (jerry_value_t value, bool release);
value - api valuerelease - raw boolean, defines whether input value must be releasedExample 1
{ jerry_value_t value; ... // create or acquire value jerry_value_t abort = jerry_create_abort_from_value (value, true); // using the 'value' variable after release is invalid. jerry_release_value (abort); }
Example 2
{ jerry_value_t value; ... // create or acquire value jerry_value_t abort = jerry_create_abort_from_value (value, false); // both 'abort' and 'value' can be used and must be released when they are no longer needed jerry_release_value (abort); jerry_release_value (value); }
See also
Summary
Create (api) error from a value.
This function creates an API error value from an API value. The second argument defines whether the input value must be released or not. If it is set to true, then a jerry_release_value function will be called for the first argument, so the api value won't be available after the call of jerry_create_error_from_value. The second argument should be false if both value and created error value are needed.
Prototype
jerry_value_t jerry_create_error_from_value (jerry_value_t value, bool release);
value - api valuerelease - raw boolean, defines whether input value must be releasedExample 1
{ jerry_value_t value; ... // create or acquire value jerry_value_t error = jerry_create_error_from_value (value, true); // using the 'value' variable after release is invalid. jerry_release_value (error); }
Example 2
{ jerry_value_t value; ... // create or acquire value jerry_value_t error = jerry_create_error_from_value (value, false); // both 'error' and 'value' can be used and must be released when they are no longer needed jerry_release_value (error); jerry_release_value (value); }
See also
Summary
Returns the type of the Error object if possible.
If a non-error object is used as the input for the function the method will return JERRY_ERROR_NONE indicating that the value was not an Error object. However it is still possible that the value contains error semantics. To correctly detect if a value have error use the jerry_value_is_error method.
Prototype
jerry_error_t jerry_get_error_type (const jerry_value_t value);
value - api value (possible error object)Example
{ jerry_value_t error_obj = jerry_create_error (JERRY_ERROR_RANGE, (const jerry_char_t *) "error msg"); jerry_error_t error_type = jerry_get_error_type (error_obj); // error_type is now JERRY_ERROR_RANGE. jerry_release_value (error_obj); }
See also
Summary
Get the value from an error.
Many API functions cannot be called with an error value. This function extracts the API value from an error. The second argument defines whether the input error value must be released or not. If it is set to true, then a jerry_release_value function will be called for the first argument, so the error value won't be available after the call of jerry_get_value_from_error. The second argument should be false if both error and its represented value are needed.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_get_value_from_error (jerry_value_t value, bool release)
value - error (api) valuerelease - raw boolean, defines whether input value must be releasedExample 1
{ jerry_value_t value; ... // create or acquire value jerry_value_t error = jerry_create_error_from_value (value, true); jerry_value_t value_from_error = jerry_get_value_from_error (error, true); // using the 'error' variable after release is invalid. jerry_release_value (value_from_error); }
Example 2
{ jerry_value_t value; ... // create or acquire value jerry_value_t error = jerry_create_error_from_value (value, true); jerry_value_t value_from_error = jerry_get_value_from_error (error, false); // both 'error' and 'value_from_error' can be used and must be released when they are no longer needed jerry_release_value (value_from_error); jerry_release_value (error); }
See also
Get raw data from API values.
Summary
Gets the raw bool value from a jerry_value_t.
Prototype
bool jerry_get_boolean_value (const jerry_value_t value);
value - api valueExample
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_boolean (value)) { bool raw_value = jerry_get_boolean_value (value); ... // usage of raw value } jerry_release_value (value); }
See also
Summary
Gets the number value of the given jerry_value_t parameter as a raw double.
Prototype
double jerry_get_number_value (const jerry_value_t value);
value - api valuejerry_value_t parameter as a raw double.Example
{ jerry_value_t value; ... // create or acquire value if (jerry_value_is_number (value)) { double raw_value = jerry_get_number_value (value); ... // usage of raw value } jerry_release_value (value); }
See also
Summary
Get the size of a string. Returns zero, if the value parameter is not a string.
Prototype
jerry_size_t jerry_get_string_size (const jerry_value_t value);
value - api valueExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string = jerry_create_string (char_array); jerry_size_t string_size = jerry_get_string_size (string); ... // usage of string_size jerry_release_value (string); }
See also
Summary
Get the size of an utf8-encoded string. Returns zero, if the value parameter is not a string.
Note: The difference from jerry_get_string_size is that it returns with utf-8 string size instead of the cesu-8 string size.
Prototype
jerry_size_t jerry_get_utf8_string_size (const jerry_value_t value);
value - api valueExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string = jerry_create_string (char_array); jerry_size_t string_size = jerry_get_utf8_string_size (string); ... // usage of string_size jerry_release_value (string); }
See also
Summary
Get the length of a string. Returns zero, if the value parameter is not a string.
Prototype
jerry_length_t jerry_get_string_length (const jerry_value_t value);
value - api valueExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string = jerry_create_string (char_array); jerry_length_t string_length = jerry_get_string_length (string); ... // usage of string_length jerry_release_value (string); }
See also
Summary
Get the length of an UTF-8 encoded string. Returns zero, if the value parameter is not a string.
Note: The difference from jerry_get_string_length is that it returns with utf-8 string length instead of the cesu-8 string length.
Prototype
jerry_length_t jerry_get_utf8_string_length (const jerry_value_t value);
value - input string valueExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string = jerry_create_string_from_utf8 (char_array); jerry_length_t string_length = jerry_get_utf8_string_length (string); ... // usage of string_length jerry_release_value (string); }
See also
Summary
Copy the characters of a string into a specified cesu-8 buffer. The '\0' character could occur in the character buffer. Returns 0, if the value parameter is not a string or the buffer is not large enough for the whole string.
Note: Does not put '\0' to the end of string, the return value identifies the number of valid bytes in the output buffer.
Note: If the size of the string in jerry value is larger than the size of the target buffer, the copy will fail. To copy a substring the jerry_substring_to_char_buffer API function is recommended instead.
Prototype
jerry_size_t jerry_string_to_char_buffer (const jerry_value_t value, jerry_char_t *buffer_p, jerry_size_t buffer_size);
value - input string valuebuffer_p - pointer to output bufferbuffer_size - size of the bufferExample
{ jerry_value_t value; ... // create or acquire value jerry_size_t req_sz = jerry_get_string_size (value); jerry_char_t str_buf_p[req_sz]; jerry_string_to_char_buffer (value, str_buf_p, req_sz); jerry_release_value (value); }
See also
Summary
Copy the characters of a string into a specified utf-8 buffer. The '\0' character could occur in character buffer. Returns 0, if the value parameter is not a string or the buffer is not large enough for the whole string.
Note: Does not put '\0' to the end of string, the return value identifies the number of valid bytes in the output buffer.
Note: If the size of the string in jerry value is larger than the size of the target buffer, the copy will fail. To copy a substring the jerry_substring_to_utf8_char_buffer API function is recommended instead.
Prototype
jerry_size_t jerry_string_to_utf8_char_buffer (const jerry_value_t value, jerry_char_t *buffer_p, jerry_size_t buffer_size);
value - input string valuebuffer_p - pointer to output bufferbuffer_size - size of the bufferExample
{ jerry_value_t value; ... // create or acquire value jerry_size_t req_sz = jerry_get_utf8_string_size (value); jerry_char_t str_buf_p[req_sz]; jerry_string_to_utf8_char_buffer (value, str_buf_p, req_sz); jerry_release_value (value); }
See also
Summary
Copy the characters of a cesu-8 encoded substring into a specified buffer. The '\0' character could occur in character buffer. Returns 0, if the value parameter is not a string. It will extract the substring between the specified start position and the end position (or the end of the string, whichever comes first).
Note: Does not put '\0' to the end of string, the return value identifies the number of valid bytes in the output buffer.
Prototype
jerry_size_t jerry_substring_to_char_buffer (const jerry_value_t value, jerry_length_t start_pos, jerry_length_t end_pos, jerry_char_t *buffer_p, jerry_size_t buffer_size);
value - input string valuestart_pos - position of the first characterend_pos - position of the last characterbuffer_p - pointer to output bufferbuffer_size - size of the bufferExample
{ jerry_value_t value; ... // create or acquire value jerry_size_t req_sz = jerry_get_string_size (value); jerry_char_t str_buf_p[req_sz]; jerry_length_t start_pos = 0; jerry_length_t end_pos = jerry_get_string_length (value); jerry_substring_to_char_buffer (value, start_pos, end_pos, str_buf_p, req_sz); jerry_release_value (value); }
See also
Summary
Copy the characters of an utf-8 encoded substring into a specified buffer. The '\0' character could occur in character buffer. Returns 0, if the value parameter is not a string. It will extract the substring between the specified start position and the end position (or the end of the string, whichever comes first).
Note: Does not put '\0' to the end of string, the return value identifies the number of valid bytes in the output buffer.
Prototype
jerry_size_t jerry_substring_to_utf8_char_buffer (const jerry_value_t value, jerry_length_t start_pos, jerry_length_t end_pos, jerry_char_t *buffer_p, jerry_size_t buffer_size);
value - input string valuestart_pos - position of the first characterend_pos - position of the last characterbuffer_p - pointer to output bufferbuffer_size - size of the bufferExample
{ jerry_value_t value; ... // create or acquire value jerry_size_t req_sz = jerry_get_utf8_string_size (value); jerry_char_t str_buf_p[req_sz]; jerry_length_t start_pos = 0; jerry_length_t end_pos = jerry_get_utf8_string_length (value); jerry_substring_to_utf8_char_buffer (value, start_pos, end_pos, str_buf_p, req_sz); jerry_release_value (value); }
See also
Summary
Get length of an array object. Returns zero, if the given parameter is not an array object.
Prototype
uint32_t jerry_get_array_length (const jerry_value_t value);
value - input array valueExample
{ jerry_value_t value; ... // create or acquire value uint32_t len = jerry_get_array_length (value); jerry_release_value (value); }
See also
Functions for converting API values to another value type.
Summary
Call ToBoolean operation on the api value.
Prototype
bool jerry_value_to_boolean (const jerry_value_t value);
value - api valueExample
{ jerry_value_t value; ... // create or acquire value bool b = jerry_value_to_boolean (value); jerry_release_value (value); }
See also
Summary
Call ToNumber operation on the api value.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_value_to_number (const jerry_value_t value);
value - api valueExample
{ jerry_value_t value; ... // create or acquire value jerry_value_t number_value = jerry_value_to_number (value); jerry_release_value (number_value); jerry_release_value (value); }
See also
Summary
Call ToObject operation on the api value.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_value_to_object (const jerry_value_t value);
value - api valueExample
{ jerry_value_t value; ... // create or acquire value jerry_value_t object_value = jerry_value_to_object (value); jerry_release_value (object_value); jerry_release_value (value); }
See also
Summary
Call ToPrimitive operation on the api value.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_value_to_primitive (const jerry_value_t value);
value - api valueExample
{ jerry_value_t value; ... // create or acquire value jerry_value_t prim_value = jerry_value_to_primitive (value); jerry_release_value (prim_value); jerry_release_value (value); }
See also
Summary
Call the ToString ecma builtin operation on the api value.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_value_to_string (const jerry_value_t value);
value - api valueExample
{ jerry_value_t value; ... // create or acquire value jerry_value_t string_value = jerry_value_to_string (value); jerry_release_value (string_value); jerry_release_value (value); }
See also
These APIs all depends on the ES2015-subset profile.
Summary
Resolve or reject the promise with an argument.
Prototype
jerry_value_t jerry_resolve_or_reject_promise (jerry_value_t promise, jerry_value_t argument, bool is_resolve)
promise - the promise valueargument - the argument for resolve or rejectis_resolve - whether the promise should be resolved or rejectedExample
{ jerry_value_t promise = ... // acquire/create a promise object. ... bool is_resolve = ... // whether the promise should be resolved or rejected jerry_value_t argument = ... // prepare the argumnent for the resolve or reject. jerry_value_t is_ok = jerry_resolve_or_reject_promise (promise, argument, is_resolve); if (jerry_value_is_error (is_ok)) { // handle the error. } jerry_release_value (is_ok); jerry_release_value (argument); jerry_release_value (promise); }
See also
Summary
Acquires the specified Jerry API value.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_acquire_value (jerry_value_t value);
value - api valueExample
{ jerry_value_t object_value = jerry_create_object (); jerry_value_t acquired_object = jerry_acquire_value (object_value); jerry_release_value (object_value); // acquired_object refers to the created object and makes it // available after the release of 'object_value' jerry_release_value (acquired_object); }
See also
Summary
Release specified Jerry API value.
Prototype
void jerry_release_value (jerry_value_t value);
value - api valueExample
{ jerry_value_t object_value = jerry_create_object (); ... jerry_release_value (object_value); }
Function for creating API values.
Note: Every created API value must be freed with jerry_release_value when it is no longer needed.
Summary
Create an array object value.
Prototype
jerry_value_t jerry_create_array (uint32_t size);
size - size of array;Example
{ jerry_value_t array = jerry_create_array (10); ... jerry_release_value (array); }
See also
Summary
Create a jerry_value_t representing an ArrayBuffer object.
Prototype
jerry_value_t jerry_create_arraybuffer (jerry_length_t size);
size - size of the ArrayBuffer to create in bytesjerry_value_tExample
{ jerry_value_t buffer_value = jerry_create_arraybuffer (15); ... // use the ArrayBuffer jerry_release_value (buffer_value); }
See also
Summary
Creates a jerry_value_t representing an ArrayBuffer object with user specified back-buffer.
User must pass a buffer pointer which is at least size big. After the object is not needed the GC will call the free_cb so the user can release the buffer which was provided.
Prototype
jerry_value_t jerry_create_arraybuffer_external (const jerry_length_t size uint8_t *buffer_p, jerry_object_native_free_callback_t free_cb);
size - size of the buffer to use in bytes (should not be 0)buffer_p - the buffer used for the Array Buffer object (should not be a null pointer)free_cb - the callback function called when the object is releasedjerry_value_tsize is zero or buffer_p is a null pointer will return RangeErrorExample
{ uint8_t buffer_p[15]; jerry_value_t buffer_value = jerry_create_arraybuffer_external (15, buffer_p, NULL); ... // use the array buffer jerry_release_value (buffer_value); }
See also
Summary
Create a jerry_value_t representing a boolean value from the given boolean parameter.
Prototype
jerry_value_t jerry_create_boolean (bool value);
value - raw boolean value.jerry_value_t created from the given boolean argument.Example
{ jerry_value_t boolean_value = jerry_create_boolean (true); ... // usage of the value jerry_release_value (boolean_value); }
See also
Summary
Create new JavaScript error object.
Important! The error_type argument must not be JERRY_ERROR_NONE. Creating an error with no error type is not valid.
Prototype
jerry_value_t jerry_create_error (jerry_error_t error_type, const jerry_char_t *message_p);
error_type - type of errormessage_p - value of 'message' property of constructed error objectExample
{ jerry_value_t error_obj = jerry_create_error (JERRY_ERROR_TYPE, (const jerry_char_t *) "error"); ... // usage of error_obj jerry_release_value (error_obj); }
See also
Summary
Create new JavaScript error object.
Prototype
jerry_value_t jerry_create_error_sz (jerry_error_t error_type, const jerry_char_t *message_p, jerry_size_t message_size);
error_type - type of the errormessage_p - value of 'message' property of the constructed error objectmessage_size - size of the message in bytesExample
{ const jerry_char_t message[] = "error"; jerry_value_t error_obj = jerry_create_error_sz (JERRY_ERROR_COMMON, message, sizeof (message) - 1); ... // usage of error_obj jerry_release_value (error_obj); }
See also
Summary
Create an external function object.
Prototype
jerry_value_t jerry_create_external_function (jerry_external_handler_t handler_p);
handler_p - pointer to native handler of the function objectExample
static jerry_value_t handler (const jerry_value_t function_obj, const jerry_value_t this_val, const jerry_value_t args_p[], const jerry_length_t args_cnt) { printf ("native handler called!\n"); return jerry_create_boolean (true); } { jerry_value_t func_val = jerry_create_external_function (handler); jerry_value_t glob_obj = jerry_get_global_object (); // after this, script can invoke the native handler through "handler_field (1, 2, 3);" jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "handler_field"); // set property and release the return value without any check jerry_release_value (jerry_set_property (glob_obj, prop_name, func_val)); jerry_release_value (prop_name); jerry_release_value (func_val); jerry_release_value (glob_obj); }
See also
Summary
Creates a jerry_value_t representing a number value.
Prototype
jerry_value_t jerry_create_number (double value);
value - double value from which a jerry_value_t will be createdjerry_value_t created from the given double argumentExample
{ jerry_value_t number_value = jerry_create_number (3.14); ... // usage of the value jerry_release_value (number_value); }
See also
Summary
Creates a jerry_value_t representing a positive or negative infinity value.
Prototype
jerry_value_t jerry_create_number_infinity (bool sign);
sign - true for negative Infinity and false for positive Infinityjerry_value_t representing the infinity valueExample
{ jerry_value_t positive_inf_value = jerry_create_number_infinity (false); ... // usage of the positive_inf_value jerry_release_value (positive_inf_value); }
See also
Summary
Creates a jerry_value_t representing a not-a-number value.
Prototype
jerry_value_t jerry_create_number_nan (void);
jerry_value_t representing the not-a-number valueExample
{ jerry_value_t nan_value = jerry_create_number_nan (); ... // usage of the nan_value jerry_release_value (nan_value); }
See also
Summary
Creates and returns a jerry_value_t with type null object.
Prototype
jerry_value_t jerry_create_null (void);
jerry_value_t representing null.Example
{ jerry_value_t null_value = jerry_create_null (); ... // usage of the value jerry_release_value (null_value); }
See also
Summary
Create new JavaScript object, like with new Object().
Prototype
jerry_value_t jerry_create_object (void);
Example
{ jerry_value_t object_value = jerry_create_object (); ... // usage of object_value jerry_release_value (object_value); }
See also
Summary
Create an empty promise object which can be resolved or rejected later by calling jerry_resolve_or_reject_promise.
Note: This API depends on the ES2015-subset profile.
Prototype
jerry_value_t jerry_create_promise (void)
Example
{ jerry_value_t p = jerry_create_promise (); ...// usage of the promise jerry_release_value (p); }
See also
Summary
Create string from a valid CESU8 string.
Prototype
jerry_value_t jerry_create_string (const jerry_char_t *str_p);
str_p - pointer to stringExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string_value = jerry_create_string (char_array); ... // usage of string_value jerry_release_value (string_value); }
See also
Summary
Create string from a valid CESU8 string.
Prototype
jerry_value_t jerry_create_string_sz (const jerry_char_t *str_p, jerry_size_t str_size)
str_p - pointer to stringstr_size - size of the stringExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string_value = jerry_create_string_sz (char_array, sizeof (char_array) - 1); ... // usage of string_value jerry_release_value (string_value); }
See also
Summary
Create string from a valid UTF8 string.
Note: The difference from jerry_create_string is that it accepts utf-8 string instead of cesu-8 string.
Prototype
jerry_value_t jerry_create_string_from_utf8 (const jerry_char_t *str_p);
str_p - pointer to stringExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string_value = jerry_create_string_from_utf8 (char_array); ... // usage of string_value jerry_release_value (string_value); }
See also
Summary
Create string from a valid UTF8 string.
Note: The difference from jerry_create_string_sz is that it accepts utf-8 string instead of cesu-8 string.
Prototype
jerry_value_t jerry_create_string_sz (const jerry_char_t *str_p, jerry_size_t str_size)
str_p - pointer to stringstr_size - size of the stringExample
{ const jerry_char_t char_array[] = "a string"; jerry_value_t string_value = jerry_create_string_sz_from_utf8 (char_array, sizeof (char_array) - 1); ... // usage of string_value jerry_release_value (string_value); }
See also
Summary
Create a jerry_value_t representing an TypedArray object.
For the new object the type of the TypedArray (see: jerry_typedarray_type_t) and element count can be specified.
Prototype
jerry_value_t jerry_create_typedarray (jerry_typedarray_type_t type_name, jerry_length_t item_count);
type_name - type of TypedArray to createitem_count - number of items in the new TypedArrayjerry_value_tExample
{ jerry_value_t array = jerry_create_typedarray (JERRY_TYPEDARRAY_UINT16, 15); ... // use the TypedArray jerry_release_value (array); }
See also
Summary
Create a jerry_value_t representing an TypedArray object using an already existing ArrayBuffer object.
For the new object the type of the TypedArray (see: jerry_typedarray_type_t) and element count can be specified.
The developer must ensure that the ArrayBuffer has the correct length for the given type of TypedArray otherwise an error is generated.
The JavaScript equivalent of this function is: new %TypedArray%(arraybuffer) where %TypedArray% is one of the allowed TypedArray functions.
Prototype
jerry_value_t jerry_create_typedarray_for_arraybuffer (jerry_typedarray_type_t type_name, const jerry_value_t arraybuffer);
type_name - type of TypedArray to createarraybuffer - the ArrayBuffer to use for the new TypedArrayjerry_value_tExample
{ jerry_value_t buffer = jerry_create_array_buffer (12 * 2); jerry_value_t array = jerry_create_typedarray_for_arraybuffer (JERRY_TYPEDARRAY_UINT16, buffer); jerry_release_value (buffer); ... // use the TypedArray jerry_release_value (array); }
See also
Summary
Create a jerry_value_t representing an TypedArray object using an already existing ArrayBuffer object and by specifying the byteOffset, and length properties.
For the new object the type of the TypedArray (see: jerry_typedarray_type_t) and element count can be specified.
The developer must ensure that the ArrayBuffer has the correct length for the given type of TypedArray otherwise an error is generated.
The JavaScript equivalent of this function is: new %TypedArray%(arraybuffer, byteOffset, length) where %TypedArray% is one of the allowed TypedArray functions.
Prototype
jerry_value_t jerry_create_typedarray_for_arraybuffer_sz (jerry_typedarray_type_t type_name, const jerry_value_t arraybuffer, jerry_length_t byte_offset, jerry_length_t length);
type_name - type of TypedArray to createarraybuffer - the ArrayBuffer to use for the new TypedArraybyte_offset - start offset to use for the ArrayBufferlength - number of elements to used from the ArrayBuffer (this is not the same as the byteLength)jerry_value_tExample
{ jerry_value_t buffer = jerry_create_array_buffer (12 * 2); jerry_value_t array = jerry_create_typedarray_for_arraybuffer_sz (JERRY_TYPEDARRAY_UINT16, buffer, 4, 10); jerry_release_value (buffer); ... // use the TypedArray jerry_release_value (array); }
See also
Summary
Creates a jerry_value_t representing an undefined value.
Prototype
jerry_value_t jerry_create_undefined (void);
Example
{ jerry_value_t undefined_value = jerry_create_undefined (); ... // usage of the value jerry_release_value (undefined_value); }
See also
Summary
Checks whether the object or its prototype objects have the given property.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_has_property (const jerry_value_t obj_val, const jerry_value_t prop_name_val);
obj_val - object valueprop_name_val - property nameExample
{ jerry_value_t global_object = jerry_get_global_object (); jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "handler_field"); jerry_value_t has_prop_js = jerry_has_property (global_object, prop_name); bool has_prop = jerry_get_boolean_value (has_prop_js); jerry_release_value (has_prop_js); jerry_release_value (prop_name); jerry_release_value (global_object); }
See also
Summary
Checks whether the object has the given property.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_has_own_property (const jerry_value_t obj_val, const jerry_value_t prop_name_val);
obj_val - object valueprop_name_val - property nameExample
{ jerry_value_t global_object = jerry_get_global_object (); jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "handler_field"); jerry_value_t has_prop_js = jerry_has_own_property (global_object, prop_name); bool has_prop = jerry_get_boolean_value (has_prop_js); jerry_release_value (jas_prop_js); jerry_release_value (prop_name); jerry_release_value (global_object); }
See also
Summary
Delete a property from an object.
Prototype
bool jerry_delete_property (const jerry_value_t obj_val, const jerry_value_t prop_name_val);
obj_val - object valueprop_name_val - property nameExample
{ jerry_value_t global_object = jerry_get_global_object (); jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "my_prop"); jerry_delete_property (global_object, prop_name); jerry_release_value (prop_name); jerry_release_value (global_object); }
See also
Summary
Delete indexed property from the specified object.
Prototype
bool jerry_delete_property_by_index (const jerry_value_t obj_val, uint32_t index);
obj_val - object valueindex - index numberExample
{ jerry_value_t object; ... // create or acquire object jerry_delete_property_by_index (object, 5); jerry_release_value (object); }
See also
Summary
Get value of a property to the specified object with the given name.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_get_property (const jerry_value_t obj_val, const jerry_value_t prop_name_val);
obj_val - object valueprop_name_val - property nameExample
{ jerry_value_t global_object = jerry_get_global_object (); jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "my_prop"); jerry_value_t prop_value = jerry_get_property (obj_val, prop_name); jerry_release_value (prop_name); jerry_release_value (global_object); }
See also
Summary
Get value by an index from the specified object.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_get_property_by_index (const jerry_value_t obj_val, uint32_t index);
obj_val - object valueindex - index numberExample
{ jerry_value_t object; ... // create or acquire object jerry_value_t value = jerry_get_property_by_index (object, 5); ... jerry_release_value (value); jerry_release_value (object); }
See also
Summary
Set a property to the specified object with the given name.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_set_property (const jerry_value_t obj_val, const jerry_value_t prop_name_val, const jerry_value_t value_to_set)
obj_val - object valueprop_name_val - property namevalue_to_set - value to setExample
{ jerry_value_t value_to_set; ... // create or acquire value to set jerry_value_t glob_obj = jerry_get_global_object (); jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "my_prop"); jerry_value_t set_result = jerry_set_property (glob_obj, prop_name, value_to_set); ... // check result of property set call jerry_release_value (set_result); jerry_release_value (prop_name); ... jerry_release_value (value_to_set); jerry_release_value (glob_obj); }
See also
Summary
Set indexed value in the specified object
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_set_property_by_index (const jerry_value_t obj_val, uint32_t index, const jerry_value_t value_to_set);
obj_val - object valueindex - index numbervalue_to_set - value to setExample
{ jerry_value_t object; jerry_value_t value_to_set; ... // create or acquire object and value to set jerry_value_t ret_val = jerry_set_property_by_index (object, 5, value_to_set); ... jerry_release_value (value_to_set); jerry_release_value (ret_val); jerry_release_value (object); }
See also
Summary
Initialize property descriptor.
Prototype
void jerry_init_property_descriptor_fields (jerry_property_descriptor_t *prop_desc_p);
prop_desc_p - pointer to property descriptorExample
{ jerry_property_descriptor_t prop_desc; jerry_init_property_descriptor_fields (&prop_desc); ... // usage of prop_desc jerry_free_property_descriptor_fields (&prop_desc); }
See also
Summary
Define a property to the specified object with the given name.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_define_own_property (const jerry_value_t obj_val, const jerry_value_t prop_name_val, const jerry_property_descriptor_t *prop_desc_p);
obj_val - object valueprop_name_val - property nameprop_desc_p - pointer to property descriptorExample
{ jerry_value_t global_obj_val = jerry_get_global_object (); jerry_property_descriptor_t prop_desc; jerry_init_property_descriptor_fields (&prop_desc); jerry_value_t value_to_set; ... // create or acquire value to set prop_desc.is_value_defined = true; prop_desc.value = value_to_set; jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "my_prop"); jerry_value_t return_value = jerry_define_own_property (global_obj_val, prop_name, &prop_desc); jerry_release_value (return_value); jerry_release_value (prop_name); jerry_free_property_descriptor_fields (&prop_desc); jerry_release_value (global_obj_val); }
See also
Summary
Construct property descriptor from specified property.
Prototype
bool jerry_get_own_property_descriptor (const jerry_value_t obj_val, const jerry_value_t prop_name_val, jerry_property_descriptor_t *prop_desc_p);
obj_val - object valueprop_name_val - property nameprop_desc_p - pointer to property descriptorExample
{ jerry_value_t global_obj_val = jerry_get_global_object (); jerry_property_descriptor_t prop_desc; jerry_init_property_descriptor_fields (&prop_desc); jerry_value_t prop_name = jerry_create_string ((const jerry_char_t *) "my_prop"); jerry_get_own_property_descriptor (global_obj_val, prop_name, &prop_desc); jerry_release_value (prop_name); ... // usage of property descriptor jerry_free_property_descriptor_fields (&prop_desc); jerry_release_value (global_obj_val); }
See also
Summary
Free fields of property descriptor (setter, getter and value).
Prototype
void jerry_free_property_descriptor_fields (const jerry_property_descriptor_t *prop_desc_p);
prop_desc_p - pointer to property descriptorExample
{ jerry_property_descriptor_t prop_desc; jerry_init_property_descriptor_fields (&prop_desc); ... // usage of property descriptor jerry_free_property_descriptor_fields (&prop_desc); }
See also
Summary
Call function specified by a function value. Error flag must not be set for any arguments of this function. Value of this parameter should be set to undefined for non-method calls.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_call_function (const jerry_value_t func_obj_val, const jerry_value_t this_val, const jerry_value_t args_p[], jerry_size_t args_count);
func_obj_val - the function object to callthis_val - object for 'this' bindingargs_p - function's call argumentsargs_count - number of argumentsExample
{ jerry_value_t val; ... // receiving val if (jerry_value_is_function (val)) { jerry_value_t this_val = jerry_create_undefined (); jerry_value_t ret_val = jerry_call_function (val, this_val, NULL, 0); if (!jerry_value_is_error (ret_val)) { ... // handle return value } jerry_release_value (ret_val); jerry_release_value (this_val); } jerry_release_value (val); }
See also
Summary
Construct object, invoking specified function object as constructor. Error flag must not be set for any arguments of this function.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_construct_object (const jerry_value_t func_obj_val, const jerry_value_t args_p[], jerry_size_t args_count);
func_obj_val - function object to callargs_p - function's call argumentsargs_count - number of argumentsExample
{ jerry_value_t val; ... // receiving val if (jerry_is_constructor (val)) { jerry_value_t ret_val = jerry_construct_object (val, NULL, 0); if (!jerry_value_is_error (ret_val)) { ... // handle return value } jerry_release_value (ret_val); } }
See also
Summary
Get keys of the specified object value.
Prototype
jerry_value_t jerry_get_object_keys (const jerry_value_t obj_val);
obj_val - object valueExample
{ jerry_value_t object; ... // create or acquire object jerry_value_t keys_array = jerry_get_object_keys (object); ... // usage of keys_array jerry_release_value (keys_array); }
See also
Summary
Get the prototype of the specified object.
Prototype
jerry_value_t jerry_get_prototype (const jerry_value_t obj_val);
obj_val - object valueExample
{ jerry_value_t object; ... // create or acquire object jerry_value_t prototype = jerry_get_prototype (object); ... // usage of prototype object jerry_release_value (prototype); jerry_release_value (object); }
See also
Summary
Set the prototype of the specified object.
Prototype
jerry_value_t jerry_set_prototype (const jerry_value_t obj_val, const jerry_value_t proto_obj_val);
obj_val - object valueproto_obj_val - prototype object valueExample
{ jerry_value_t object; jerry_value_t prototype; ... // create or acquire object and prototype jerry_value_t ret_val = jerry_set_prototype (object, prototype); jerry_release_value (ret_val); jerry_release_value (prototype); jerry_release_value (object); }
See also
Summary
Get native pointer and its type information. The pointer and the type information are previously associated with the object by jerry_set_object_native_pointer.
Note: It is recommended to ensure that the out_native_info_p value pointer is equal to the native info pointer that is expected, before casting and accessing the out_native_pointer_p. An example of when this is important: external functions that expect this to have a native pointer of a certain C type. It is possible in JavaScript to change this at will – using call(), apply() or bind(). Therefore, it is possible that the native pointer of this is not of the expected C type. To handle this safely and securely, one must always add type checks to make sure that the out_native_pointer_p is of the expected type, before casting and dereferencing out_native_pointer_p.
Note: out_native_pointer_p and out_native_info_p can be NULL, and it means the caller doesn't want to get the native_pointer or type information.
Prototype
bool jerry_get_object_native_pointer (const jerry_value_t obj_val, void **out_native_pointer_p, const jerry_object_native_info_t **out_native_info_p)
obj_val - object value to get native pointer from.out_native_pointer_p - native pointer (output parameter).out_native_info_p - native pointer's type information (output parameter).Example
typedef struct { int foo; bool bar; } native_obj_t; static void native_freecb (void *native_p) { ... // free the native pointer } // NOTE: The address (!) of type_info acts as a way to uniquely "identify" the // C type `native_obj_t *`. static const jerry_object_native_info_t native_obj_type_info = { .free_cb = native_freecb }; // Function creating JS object that is "backed" by a native_obj_t *: { ... // construct object and native_set value: jerry_value_t object = ...; native_obj_t *native_obj = malloc(sizeof(*native_obj)); jerry_set_object_native_pointer (object, native_obj, &native_obj_type_info); ... } // Native method, `this` is expected to be "backed" by a native_obj_t *: { void *native_p; const jerry_object_native_info_t *type_p; bool has_p = jerry_get_object_native_pointer (this_val, &native_p, &type_p); if (has_p) { // The type_p pointer address itself is used to identify the type: if (type_p == &native_obj_type_info) { // The type of this's native pointer matches what is expected. // Only now is it safe to cast to native_obj_t * and dereference the // pointer: native_obj_t *native_obj = native_p; native_obj->bar = ...; // Safe to access now! } else { // The type of this's native pointer is NOT what we expected! // We should not cast to native_obj_t * and dereference because it's unsafe. // Handle the error here, for example throw an error. } } ... }
See also
Summary
Set native pointer and an optional type information for the specified object. You can get them by calling jerry_get_object_native_pointer later.
Note: If native pointer was already set for the object, its value is updated.
Note: If a non-NULL free callback is specified in the native type information, it will be called by the garbage collector when the object is freed. The type info is always overwrites the previous value, so passing a NULL value deletes the current type info.
Prototype
bool jerry_set_object_native_pointer (const jerry_value_t obj_val, void *native_p, const jerry_object_native_info_t *info_p)
obj_val - object to set native pointer in.native_p - native pointer.info_p - native pointer's type information or NULL. When used, this should be a long-lived pointer, usually a pointer to a static const jerry_object_native_info_t makes most sense.Example
See jerry_get_object_native_pointer for a best-practice example.
See also
Summary
Applies the given function to every property in the given object.
Prototype
bool jerry_foreach_object_property (jerry_value_t obj_val, jerry_object_property_foreach_t foreach_p, void *user_data_p);
obj_val - object valueforeach_p - foreach function, that will be applied for each propertyuser_data_p - user data for foreach functionExample
bool foreach_function (const jerry_value_t prop_name, const jerry_value_t prop_value, void *user_data_p) { ... // implementation of the foreach function } { jerry_value_t object; ... // receive or construct object double data = 3.14; // example data jerry_foreach_object_property (object, foreach_function, &data); }
See also
Summary
Iterate over objects.
Note: Values obtained in foreach_p must be retained using jerry_acquire_value.
Prototype
bool jerry_objects_foreach (jerry_objects_foreach_t foreach_p, void *user_data_p);
foreach_p - function that will be invoked for each object.user_data_p - User data to pass to the function.true, if the search function terminated the traversal by returning falsefalse, if the end of the list of objects was reachedExample
typedef struct { jerry_value_t property_name; jerry_value_t result; } find_my_object_info_t; /* * Find the first object with the given property. */ static bool find_my_object(const jerry_value_t candidate, void *user_data_p) { find_my_object_info_t *info_p = (find_my_object_info_t *) user_data_p; jerry_value_t has_property = jerry_object_has_property (candidate, info_p->property_name); bool keep_searching = (jerry_value_is_error (has_property) || !jerry_get_boolean_value ()); if (!keep_searching) { /* We found it, so we acquire the value and record it. */ info_p->result = jerry_acquire_value (candidate); } jerry_release_value (has_property); return keep_searching; } /* find_my_object */ { find_my_object_info_t search_info = { .property_name = jerry_create_string ("desired_property") }; if (jerry_object_foreach (find_my_object, &search_info)) { /* The search was successful. Do something useful with search_info.result. */ ... /* Release the found object after we're done using it. */ jerry_release_value (search_info.result); } else { /* The search has failed. */ } jerry_release_value (search_info.desired_property); }
See also
Summary
Iterate over objects matching a certain native data type.
Note: Values obtained in foreach_p must be retained using jerry_acquire_value.
Prototype
bool jerry_objects_foreach_by_native_info (const jerry_object_native_info_t *native_info_p, jerry_objects_foreach_by_native_info_t foreach_p, void *user_data_p);
native_info_p - native pointer's type information.true, if the search function terminated the traversal by returning falsefalse, if the end of the list of objects was reachedExample
typedef struct { int foo; bool bar; } native_obj_t; typedef struct { jerry_value_t found_object; void *match_data_p; } find_object_data_t; static void native_freecb (void *native_p) { ... // free the native pointer } /* native_freecb */ // NOTE: The address (!) of type_info acts as a way to uniquely "identify" the // C type `native_obj_t *`. static const jerry_object_native_info_t native_obj_type_info = { .free_cb = native_freecb }; // Function creating JS object that is "backed" by a native_obj_t *: { ... // construct object and native_set value: jerry_value_t object = ...; native_obj_t *native_obj_p = malloc (sizeof (*native_obj_p)); jerry_set_object_native_pointer (object, native_obj_p, &native_obj_type_info); ... } // Native method that retrieves the JavaScript object by way of its native data: static bool find_object (const jerry_value_t candidate, void *data_p, void *user_data_p) { find_object_data_t *find_data_p = (find_object_data_t *) user_data_p; if (find_data_p->match_data_p == data_p) { // If the object was found, acquire it and store it in the user data. find_data_p->found_object = jerry_acquire_value (candidate); // Stop traversing over the objects. return false; } // Indicate that the object was not found, so traversal must continue. return true; } /* find_object */ ... { find_object_data_t find_data = { .match_data = native_obj }; if (jerry_objects_foreach_by_native_info (&native_obj_type_info, find_object, &find_data)) { // The object was found and is now stored in find_data.found_object. After using it, it must be released. ... jerry_release_value (find_data.found_object); } else { // The object was not found. } ... }
See also
Summary
Validate UTF-8 string.
Prototype
bool jerry_is_valid_utf8_string (const jerry_char_t *utf8_buf_p, /**< UTF-8 string */ jerry_size_t buf_size) /**< string size */
utf8_buf_p - UTF-8 input stringbuf_size - input string sizeExample
#include "jerryscript.h" int main (void) { const jerry_char_t script[] = "print ('Hello, World!');"; const jerry_size_t script_size = sizeof (script) - 1; if (jerry_is_valid_utf8_string (script, script_size)) { jerry_run_simple (script, script_size, JERRY_INIT_EMPTY); } }
See also
Summary
Validate CESU-8 string.
Prototype
bool jerry_is_valid_cesu8_string (const jerry_char_t *cesu8_buf_p, /**< CESU-8 string */ jerry_size_t buf_size) /**< string size */
cesu8_buf_p - CESU-8 input stringbuf_size - input string sizeExample
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); const jerry_char_t script[] = "Hello, World!"; const jerry_size_t script_size = sizeof (script) - 1; if (jerry_is_valid_cesu8_string (script, script_size)) { jerry_value_t string_value = jerry_create_string_sz (script, script_size); // usage of string_value jerry_release_value (string_value); } jerry_cleanup (); }
See also
Summary
Allocate memory on the engine's heap.
Note: This function may take away memory from the executed JavaScript code. If any other dynamic memory allocation API is available (e.g., libc malloc), it should be used instead.
Prototype
void *jerry_heap_alloc (size_t size);
size: size of the memory block.See also
Summary
Free memory allocated on the engine's heap.
Prototype
void jerry_heap_free (void *mem_p, size_t size);
mem_p: value returned by jerry_heap_alloc.size: same size as passed to jerry_heap_alloc.See also
Summary
Create an external JerryScript engine context.
Prototype
jerry_context_t * jerry_create_context (uint32_t heap_size, jerry_context_alloc_t alloc, void *cb_data_p);
heap_size - requested heap size of the JerryScript contextalloc - function for allocationcb_data_p - user dataExample
#include <stdlib.h> #include <pthread.h> #include "jerryscript.h" #include "jerryscript-port.h" /* A different Thread Local Storage variable for each jerry context. */ __thread jerry_context_t *tls_context; jerry_context_t * jerry_port_get_current_context (void) { /* Returns the context assigned to the thread. */ return tls_context; } /* Allocate JerryScript heap for each thread. */ static void * context_alloc_fn (size_t size, void *cb_data) { (void) cb_data; return malloc (size); } static void * thread_function (void *param) { tls_context = jerry_create_context (512 * 1024, context_alloc_fn, NULL); jerry_init (JERRY_INIT_EMPTY); /* Run JerryScript in the context (e.g.: jerry_parse & jerry_run) */ jerry_cleanup (); /* Deallocate JerryScript context */ free (tls_context); return NULL; } #define NUM_OF_THREADS 8 int main (void) { pthread_t threads[NUM_OF_THREADS]; /* Create the threads. */ for (int i = 0; i < NUM_OF_THREADS; i++) { pthread_create (&threads[i], NULL, thread_function, (void *) (intptr_t) i); } /* Wait for the threads to complete, and release their resources. */ for (int i = 0; i < NUM_OF_THREADS; i++) { pthread_join (threads[i], NULL); } return 0; }
See also
Summary
Generate snapshot from the specified source code.
Prototype
jerry_value_t jerry_generate_snapshot (const jerry_char_t *resource_name_p, size_t resource_name_length, const jerry_char_t *source_p, size_t source_size, uint32_t generate_snapshot_opts, uint32_t *buffer_p, size_t buffer_size);
resource_name_p - resource (file) name of the source code. Currently unused, the debugger may use it in the future.resource_name_length - length of resource name.source_p - script source, it must be a valid utf8 string.source_size - script source size, in bytes.generate_snapshot_opts - any combination of jerry_generate_snapshot_opts_t flags.buffer_p - buffer to save snapshot to.buffer_size - the buffer's size.Example
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); static uint32_t global_mode_snapshot_buffer[256]; const jerry_char_t script_to_snapshot[] = "(function () { return 'string from snapshot'; }) ();"; jerry_value_t generate_result; generate_result = jerry_generate_snapshot (NULL, 0, script_to_snapshot, sizeof (script_to_snapshot) - 1, 0, global_mode_snapshot_buffer, sizeof (global_mode_snapshot_buffer) / sizeof (uint32_t)); size_t snapshot_size = (size_t) jerry_get_number_value (generate_result); jerry_release_value (generate_result); jerry_cleanup (); }
See also
Summary
Generate function snapshot from the specified source code with the given arguments.
The function arguments and function body are passed as separated arguments.
Prototype
jerry_value_t jerry_generate_function_snapshot (const jerry_char_t *resource_name_p, size_t resource_name_length, const jerry_char_t *source_p, size_t source_size, const jerry_char_t *args_p, size_t args_size, uint32_t generate_snapshot_opts, uint32_t *buffer_p, size_t buffer_size)
resource_name_p - resource (file) name of the source code. Currently unused, the debugger may use it in the future.resource_name_length - length of resource name.source_p - script source, it must be a valid utf8 string.source_size - script source size, in bytes.args_p - function arguments, it must be a valid utf8 string.args_size - function argument size, in bytes.generate_snapshot_opts - any combination of jerry_generate_snapshot_opts_t flags.buffer_p - buffer to save snapshot to.buffer_size - the buffer's size.Example
#include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); static uint32_t func_snapshot_buffer[256]; const jerry_char_t args[] = "a, b"; const jerry_char_t src[] = "return a + b;"; jerry_value_t generate_result; generate_result = jerry_generate_function_snapshot (NULL, 0, src, sizeof (src) - 1, args, sizeof (args) - 1, 0, func_snapshot_buffer, sizeof (func_snapshot_buffer) / sizeof (uint32_t)); size_t snapshot_size = (size_t) jerry_get_number_value (generate_result); jerry_release_value (generate_result); jerry_cleanup (); }
See also
Summary
Execute snapshot from the specified buffer.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_exec_snapshot (const uint32_t *snapshot_p, size_t snapshot_size, size_t func_index, uint32_t exec_snapshot_opts);
snapshot_p - pointer to snapshotsnapshot_size - size of snapshotfunc_index - index of executed functionexec_snapshot_opts - any combination of jerry_exec_snapshot_opts_t flags.Example
#include "jerryscript.h" int main (void) { static uint32_t global_mode_snapshot_buffer[256]; const jerry_char_t script_to_snapshot[] = "(function () { return 'string from snapshot'; }) ();"; jerry_init (JERRY_INIT_EMPTY); jerry_value_t generate_result; generate_result = jerry_generate_snapshot (NULL, 0, script_to_snapshot, sizeof (script_to_snapshot) - 1, 0, global_mode_snapshot_buffer, sizeof (global_mode_snapshot_buffer) / sizeof (uint32_t)); size_t global_mode_snapshot_size = (size_t) jerry_get_number_value (generate_result); jerry_release_value (generate_result); jerry_cleanup (); jerry_init (JERRY_INIT_EMPTY); jerry_value_t res = jerry_exec_snapshot (global_mode_snapshot_buffer, global_mode_snapshot_size, 0, 0); jerry_release_value (res); jerry_cleanup (); }
See also
Summary
Load the selected snapshot function from the specified buffer as a function object.
The lexical environment of the loaded function is always the global lexical environment.
Note: Returned value must be freed with jerry_release_value when it is no longer needed.
Prototype
jerry_value_t jerry_load_function_snapshot (const uint32_t *snapshot_p, size_t snapshot_size, size_t func_index, uint32_t exec_snapshot_opts);
snapshot_p - pointer to snapshotsnapshot_size - size of snapshotfunc_index - index of function to loadexec_snapshot_opts - any combination of jerry_exec_snapshot_opts_t flags.Example
#include "jerryscript.h" int main (void) { static uint32_t snapshot_buffer[256]; const jerry_char_t func_args[] = "a, b"; const jerry_char_t func_src[] = "return a + b;"; jerry_init (JERRY_INIT_EMPTY); jerry_value_t generate_result; generate_result = jerry_generate_function_snapshot (NULL, 0, func_src, sizeof (func_src) - 1, func_args, sizeof (func_args) - 1, false, snapshot_buffer, sizeof (snapshot_buffer) / sizeof (uint32_t)); size_t snapshot_size = (size_t) jerry_get_number_value (generate_result); jerry_release_value (generate_result); jerry_cleanup (); jerry_init (JERRY_INIT_EMPTY); jerry_value_t func = jerry_load_function_snapshot (snapshot_buffer, snapshot_size, 0, 0); /* 'func' can be used now as a function object */ jerry_value_t this_value = jerry_create_undefined (); jerry_value_t args[2]; args[0] = jerry_create_number (1.0); args[1] = jerry_create_number (2.0); jerry_value_t res = jerry_call_function (func, this_value, args, 2); /* 'res' now contains the value 3 as a jerry_value_t */ jerry_release_value (args[0]); jerry_release_value (args[1]); jerry_release_value (this_value); jerry_release_value (func); jerry_cleanup (); return 0; }
See also
Summary
Collect the used literals from the given snapshot and save them into a buffer in list or C format. None of these literals are magic strings. In C format only valid identifiers are collected.
Prototype
size_t jerry_get_literals_from_snapshot (const uint32_t *snapshot_p, size_t snapshot_size, jerry_char_t *lit_buf_p, size_t lit_buf_size, bool is_c_format);
snapshot_p - input snapshot buffer.snapshot_size - snapshot size, in bytes.lit_buf_p - buffer to save literals to.lit_buf_size - the buffer's size.is_c_format - the output format would be C-style (true) or a simple list (false).Example
#include <stdio.h> #include "jerryscript.h" int main (void) { jerry_init (JERRY_INIT_EMPTY); static jerry_char_t literal_buffer[256]; static uint32_t snapshot_buffer[256]; const jerry_char_t script_for_literal_save[] = "var obj = { a:'aa', bb:'Bb' }"; jerry_value_t generate_result = jerry_generate_snapshot (NULL, 0, script_for_literal_save, sizeof (script_for_literal_save) - 1, 0, snapshot_buffer, 256); size_t snapshot_size = (size_t) jerry_get_number_value (generate_result); jerry_release_value (generate_result); const size_t literal_size = jerry_get_literals_from_snapshot (snapshot_buffer, snapshot_size, literal_buffer, 256, true); if (literal_size != 0) { FILE *literal_file_p = fopen ("literals.h", "wb"); fwrite (literal_buffer, sizeof (uint8_t), literal_size, literal_file_p); fclose (literal_file_p); } jerry_cleanup (); }
See also
Summary
When JERRY_FEATURE_VM_EXEC_STOP is enabled a callback function can be specified by this function. This callback is periodically called when JerryScript executes an ECMAScript program.
If the callback returns with undefined value the ECMAScript execution continues. Otherwise the result is thrown by the engine (if the error flag is not set for the returned value the engine automatically sets it). The callback function might be called again even if it threw an error. In this case the function must throw the same error again.
To reduce the CPU overhead of constantly checking the termination condition the callback is called when a backward jump is executed or an exception is caught. Setting the frequency to a greater than 1 value reduces this overhead further. If its value is N only every Nth event (backward jump, etc.) trigger the next check.
Prototype
void jerry_set_vm_exec_stop_callback (jerry_vm_exec_stop_callback_t stop_cb, void *user_p, uint32_t frequency);
stop_cb - periodically called callback (passing NULL disables this feature)user_p - user pointer passed to the stop_cb functionfrequency - frequency of calling the stop_cb functionExample
#include "jerryscript.h" static int countdown = 10; static jerry_value_t vm_exec_stop_callback (void *user_p) { while (countdown > 0) { countdown--; return jerry_create_undefined (); } // The error flag is added automatically. return jerry_create_string ((const jerry_char_t *) "Abort script"); } int main (void) { jerry_init (JERRY_INIT_EMPTY); jerry_set_vm_exec_stop_callback (vm_exec_stop_callback, &countdown, 16); // Inifinte loop. const jerry_char_t script[] = "while(true) {}"; jerry_value_t parsed_code = jerry_parse (NULL, 0, script, sizeof (script) - 1, JERRY_PARSE_NO_OPTS); jerry_release_value (jerry_run (parsed_code)); jerry_release_value (parsed_code); jerry_cleanup (); }
See also
Summary
Get backtrace. The backtrace is an array of strings where each string contains the position of the corresponding frame. The array length is zero if the backtrace is not available.
This function is typically called from native callbacks.
Prototype
jerry_value_t jerry_get_backtrace (uint32_t max_depth);
max_depth - backtrace collection stops after reaching this value, 0 = unlimitedSee also
Summary
Get the byte length property of the ArrayBuffer. This is the same value which was passed to the ArrayBuffer constructor call.
Prototype
jerry_length_t jerry_get_arraybuffer_byte_length (const jerry_value_t value);
value - ArrayBuffer objectvalue parameter is not an ArrayBufferExample
{ jerry_value_t buffer = jerry_create_arraybuffer (15); jerry_length_t length = jerry_get_arraybuffer_byte_length (buffer); // length should be 15 jerry_release_value (buffer); }
See also
Summary
Copy the portion of the ArrayBuffer into a user provided buffer. The start offset of the read operation can be specified.
The number bytes to be read can be specified via the buf_size parameter. It is not possible to read more than the length of the ArrayBuffer.
Function returns the number of bytes read from the ArrayBuffer (and written to the buffer parameter). This value is calculated in the following way: min(array buffer length - offset, buf_size).
Prototype
jerry_length_t jerry_arraybuffer_read (const jerry_value_t value, jerry_length_t offset, uint8_t *buf_p, jerry_length_t buf_size);
value - ArrayBuffer to read fromoffset - start offset of the read operationbuf_p - buffer to read the data tobuf_size - maximum number of bytes to read into the buffervalue is not an ArrayBuffer objectbuf_size is zero or there is nothing to readExample
{ uint8_t data[20]; jerry_value_t buffer; // ... create the ArrayBuffer or acuiqre it from somewhere. jerry_value_t bytes_read; // read 10 bytes from the start of the ArrayBuffer. bytes_read = jerry_arraybuffer_read (buffer, 0, data, 10); // read the next 10 bytes bytes_read += jerry_arraybuffer_read (buffer, bytes_read, data + bytes_read, 10); // process the data variable jerry_release_value (buffer); }
See also
Summary
Copy the contents of a buffer into the ArrayBuffer. The start offset of the write operation can be specified.
The number bytes to be written can be specified via the buf_size parameter. It is not possible to write more than the length of the ArrayBuffer.
Function returns the number of bytes written into the ArrayBuffer (and read from the buffer parameter). This value is calculated in the following way: min(array buffer length - offset, buf_size).
Prototype
jerry_length_t jerry_arraybuffer_write (const jerry_value_t value, jerry_length_t offset, const uint8_t *buf_p, jerry_length_t buf_size);
value - ArrayBuffer to write tooffset - start offset of the write operationbuf_p - buffer to read the data frombuf_size - maximum number of bytes to write into the ArrayBuffervalue is not an ArrayBuffer objectbuf_size is zero or there is nothing to writeExample
{ uint8_t data[20]; // fill the data with values for (int i = 0; i < 20; i++) { data[i] = (uint8_t) (i * 2); } jerry_value_t buffer; // ... create the ArrayBuffer or acquire it from somewhere. jerry_value_t bytes_written; // write 10 bytes from to the start of the ArrayBuffer. bytes_written = jerry_arraybuffer_write (buffer, 0, data, 10); // read the next 10 bytes bytes_written += jerry_arraybuffer_write (buffer, bytes_written, data + bytes_written, 10); // use the ArrayBuffer jerry_release_value (buffer); }
See also
Summary
The function allows access to the contents of the Array Buffer directly. Only allowed for Array Buffers which were created with jerry_create_arraybuffer_external function calls. In any other case this function will return NULL.
After using the pointer the jerry_release_value function must be called.
WARNING! This operation is for expert use only! The programmer must ensure that the returned memory area is used correctly. That is there is no out of bounds reads or writes.
Prototype
uint8_t * jerry_get_arraybuffer_pointer (const jerry_value_t value);
value - Array Buffer object.value is not an Array Buffer object with external memory.Example
{ jerry_value_t buffer; // acquire buffer somewhere which was created by a jerry_create_array_buffer_external call. uint8_t *const data = jerry_get_arraybuffer_pointer (buffer); for (int i = 0; i < 22; i++) { data[i] = (uint8_t) (i + 4); } // required after jerry_get_arraybuffer_pointer call. jerry_release_value (buffer); // use the Array Buffer // release buffer as it is not needed after this point jerry_release_value (buffer); }
See also
Summary
Get the type of the TypedArray.
The returned type is one of the jerry_typedarray_type_t enum value.
Prototype
jerry_typedarray_type_t jerry_get_typedarray_type (jerry_value_t value);
value - TypedArray object to query for type.Example
{ jerry_typedarray_type_t expected_type = JERRY_TYPEDARRAY_UINT32; jerry_value_t typedarray = jerry_create_typedarray (expected_klass, 25); jerry_typedarray_type_t type = jerry_get_typedarray_type (typedarray); // 'type' is now JERRY_TYPEDARRAY_UINT32 jerry_release_value (typedarray); }
See also
Summary
Get the element count of the TypedArray as specified during creation.
This is not the same as the byteLength property of a TypedArray object.
Prototype
jerry_length_t jerry_get_typedarray_length (jerry_value_t value);
value - TypedArray object to queryExample
{ jerry_value_t array = jerry_create_typedarray (JERRY_TYPEDARRAY_INT32, 21); jerry_length_t element_count = jerry_get_typedarray_length (array); // element_count is now 21. jerry_release_value (array); }
See also
Summary
Get the ArrayBuffer object used by a TypedArray object. Additionally returns the byteLength and byteOffset properties of the TypedArray object.
For the returned ArrayBuffer the jerry_release_value must be called.
Prototype
jerry_value_t jerry_get_typedarray_buffer (jerry_value_t value, jerry_length_t *byteOffset, jerry_length_t *byteLength);
value - TypedArray to get the ArrayBuffer frombyteOffset - (Optional) returns the start offset of the ArrayBuffer for the TypedArraybyteLength - (Optional) returns the number of bytes used from the ArrayBuffer for the TypedArrayvalue is not a TypedArray objectExample
{ jerry_value_t array = jerry_create_typedarray (JERRY_TYPEDARRAY_INT16, 11); jerry_length_t byteLength = 0; jerry_length_t byteOffset = 0; jerry_value_t buffer = jerry_get_typedarray_buffer (array, &byteOffset, &byteLength); // buffer is an ArrayBuffer object and ArrayBuffer operations can be performed on it // byteLength is 11 * 2 (2 as the TypedArray stores Int16 that is 2 byte elements) // byteOffset is 0 jerry_release_value (buffer); jerry_release_value (array); }
See also
Summary
Returns the same result as JSON.parse ecmascript function.
Prototype
jerry_value_t jerry_json_parse (const jerry_char_t *string_p, jerry_size_t string_size)
string_p - a JSON stringstring_size - size of the stringExample
{ const jerry_char_t data[] = "{\"name\": \"John\", \"age\": 5}"; jerry_value_t parsed_json = jerry_json_parse (data, sizeof (data) - 1); // parsed_json now conatins all data stored in data_in_json jerry_release_value (parsed_json); }
Summary
Returns the same value as JSON.stringify() ecmascript function.
Prototype
jerry_value_t jerry_json_stringfy (const jerry_value_t object_to_stringify)
object_to_stringify - a jerry_value_t object to stringifyExample
{ jerry_value_t obj = jerry_create_object (); jerry_value_t key = jerry_create_string ((const jerry_char_t *) "name"); jerry_value_t value = jerry_create_string ((const jerry_char_t *) "John"); jerry_set_property (obj, key, value); jerry_value_t stringified = jerry_json_stringfy (obj); //stringified now contains a json formated string jerry_release_value (obj); jerry_release_value (key); jerry_release_value (value); jerry_release_value (stringified); }