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Overview

Use the links in the table of contents to the left to access the documentation.

Functions

JSValueGetType

Returns a JavaScript value's type.

JSValueIsBoolean

Tests whether a JavaScript value's type is the boolean type.

JSValueIsEqual

Tests whether two JavaScript values are equal, as compared by the JS == operator.

JSValueIsInstanceOfConstructor

Tests whether a JavaScript value is an object constructed by a given constructor, as compared by the JS instanceof operator.

JSValueIsNull

Tests whether a JavaScript value's type is the null type.

JSValueIsNumber

Tests whether a JavaScript value's type is the number type.

JSValueIsObject

Tests whether a JavaScript value's type is the object type.

JSValueIsObjectOfClass

Tests whether a JavaScript value is an object with a given class in its class chain.

JSValueIsStrictEqual

Tests whether two JavaScript values are strict equal, as compared by the JS === operator.

JSValueIsString

Tests whether a JavaScript value's type is the string type.

JSValueIsUndefined

Tests whether a JavaScript value's type is the undefined type.

JSValueMakeBoolean

Creates a JavaScript value of the boolean type.

JSValueMakeNull

Creates a JavaScript value of the null type.

JSValueMakeNumber

Creates a JavaScript value of the number type.

JSValueMakeString

Creates a JavaScript value of the string type.

JSValueMakeUndefined

Creates a JavaScript value of the undefined type.

JSValueProtect

Protects a JavaScript value from garbage collection.

JSValueToBoolean

Converts a JavaScript value to boolean and returns the resulting boolean.

JSValueToNumber

Converts a JavaScript value to number and returns the resulting number.

JSValueToObject

Converts a JavaScript value to object and returns the resulting object.

JSValueToStringCopy

Converts a JavaScript value to string and copies the result into a JavaScript string.

JSValueUnprotect

Unprotects a JavaScript value from garbage collection.

Returns a JavaScript value's type.

JS_EXPORT JSType JSValueGetType(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

A value of type JSType that identifies value's type.

Tests whether a JavaScript value's type is the boolean type.

JS_EXPORT bool JSValueIsBoolean(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

true if value's type is the boolean type, otherwise false.

Tests whether two JavaScript values are equal, as compared by the JS == operator.

JS_EXPORT bool JSValueIsEqual(
    JSContextRef ctx,
    JSValueRef a,
    JSValueRef b,
    JSValueRef *exception);  

Parameters

Return Value

true if the two values are equal, false if they are not equal or an exception is thrown.

Tests whether a JavaScript value is an object constructed by a given constructor, as compared by the JS instanceof operator.

JS_EXPORT bool JSValueIsInstanceOfConstructor(
    JSContextRef ctx,
    JSValueRef value,
    JSObjectRef constructor,
    JSValueRef *exception);  

Parameters

Return Value

true if value is an object constructed by constructor, as compared by the JS instanceof operator, otherwise false.

Tests whether a JavaScript value's type is the null type.

JS_EXPORT bool JSValueIsNull(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

true if value's type is the null type, otherwise false.

Tests whether a JavaScript value's type is the number type.

JS_EXPORT bool JSValueIsNumber(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

true if value's type is the number type, otherwise false.

Tests whether a JavaScript value's type is the object type.

JS_EXPORT bool JSValueIsObject(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

true if value's type is the object type, otherwise false.

Tests whether a JavaScript value is an object with a given class in its class chain.

JS_EXPORT bool JSValueIsObjectOfClass(
    JSContextRef ctx,
    JSValueRef value,
    JSClassRef jsClass);  

Parameters

Return Value

true if value is an object and has jsClass in its class chain, otherwise false.

Tests whether two JavaScript values are strict equal, as compared by the JS === operator.

JS_EXPORT bool JSValueIsStrictEqual(
    JSContextRef ctx,
    JSValueRef a,
    JSValueRef b);  

Parameters

Return Value

true if the two values are strict equal, otherwise false.

Tests whether a JavaScript value's type is the string type.

JS_EXPORT bool JSValueIsString(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

true if value's type is the string type, otherwise false.

Tests whether a JavaScript value's type is the undefined type.

JS_EXPORT bool JSValueIsUndefined(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

true if value's type is the undefined type, otherwise false.

Creates a JavaScript value of the boolean type.

JS_EXPORT JSValueRef JSValueMakeBoolean(
    JSContextRef ctx,
    bool boolean);  

Parameters

Return Value

A JSValue of the boolean type, representing the value of boolean.

Creates a JavaScript value of the null type.

JS_EXPORT JSValueRef JSValueMakeNull(
    JSContextRef ctx);  

Parameters

Return Value

The unique null value.

Creates a JavaScript value of the number type.

JS_EXPORT JSValueRef JSValueMakeNumber(
    JSContextRef ctx,
    double number);  

Parameters

Return Value

A JSValue of the number type, representing the value of number.

Creates a JavaScript value of the string type.

JS_EXPORT JSValueRef JSValueMakeString(
    JSContextRef ctx,
    JSStringRef string);  

Parameters

Return Value

A JSValue of the string type, representing the value of string.

Creates a JavaScript value of the undefined type.

JS_EXPORT JSValueRef JSValueMakeUndefined(
    JSContextRef ctx);  

Parameters

Return Value

The unique undefined value.

Protects a JavaScript value from garbage collection.

JS_EXPORT void JSValueProtect(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Discussion

Use this method when you want to store a JSValue in a global or on the heap, where the garbage collector will not be able to discover your reference to it.

A value may be protected multiple times and must be unprotected an equal number of times before becoming eligible for garbage collection.

Converts a JavaScript value to boolean and returns the resulting boolean.

JS_EXPORT bool JSValueToBoolean(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Return Value

The boolean result of conversion.

Converts a JavaScript value to number and returns the resulting number.

JS_EXPORT double JSValueToNumber(
    JSContextRef ctx,
    JSValueRef value,
    JSValueRef *exception);  

Parameters

Return Value

The numeric result of conversion, or NaN if an exception is thrown.

Converts a JavaScript value to object and returns the resulting object.

JS_EXPORT JSObjectRef JSValueToObject(
    JSContextRef ctx,
    JSValueRef value,
    JSValueRef *exception);  

Parameters

Return Value

The JSObject result of conversion, or NULL if an exception is thrown.

Converts a JavaScript value to string and copies the result into a JavaScript string.

JS_EXPORT JSStringRef JSValueToStringCopy(
    JSContextRef ctx,
    JSValueRef value,
    JSValueRef *exception);  

Parameters

Return Value

A JSString with the result of conversion, or NULL if an exception is thrown. Ownership follows the Create Rule.

Unprotects a JavaScript value from garbage collection.

JS_EXPORT void JSValueUnprotect(
    JSContextRef ctx,
    JSValueRef value);  

Parameters

Discussion

A value may be protected multiple times and must be unprotected an equal number of times before becoming eligible for garbage collection.

Typedefs

JSType

A constant identifying the type of a JSValue.

A constant identifying the type of a JSValue.

typedef enum { 
    kJSTypeUndefined, 
    kJSTypeNull, 
    kJSTypeBoolean, 
    kJSTypeNumber, 
    kJSTypeString, 
    kJSTypeObject 
} JSType;  

Constants