JS_DefineElement

Creates a numeric property on a specified object.

Syntax

/* Added in SpiderMonkey 38 (JSAPI 32) */

bool
JS_DefineElement(JSContext *cx, JS::HandleObject obj,
                 uint32_t index, JS::HandleValue value,
                 unsigned attrs,
                 JSNative getter = nullptr, JSNative setter = nullptr);

bool
JS_DefineElement(JSContext *cx, JS::HandleObject obj,
                 uint32_t index, JS::HandleObject value,
                 unsigned attrs,
                 JSNative getter = nullptr, JSNative setter = nullptr);

bool
JS_DefineElement(JSContext *cx, JS::HandleObject obj,
                 uint32_t index, JS::HandleString value,
                 unsigned attrs,
                 JSNative getter = nullptr, JSNative setter = nullptr);

bool
JS_DefineElement(JSContext *cx, JS::HandleObject obj,
                 uint32_t index, int32_t value,
                 unsigned attrs,
                 JSNative getter = nullptr, JSNative setter = nullptr);

bool
JS_DefineElement(JSContext *cx, JS::HandleObject obj,
                 uint32_t index, uint32_t value,
                 unsigned attrs,
                 JSNative getter = nullptr, JSNative setter = nullptr);

bool
JS_DefineElement(JSContext *cx, JS::HandleObject obj,
                 uint32_t index, double value,
                 unsigned attrs,
                 JSNative getter = nullptr, JSNative setter = nullptr);

/* Obsolete since JSAPI 32 */

JS_DefineElement(JSContext *cx, JSObject *obj, uint32_t index, jsval value,
                 JSPropertyOp getter, JSStrictPropertyOp setter, unsigned attrs);

Name	Type	Description
`cx`	`JSContext *`	The context in which to create the new property. Requires request. In a `JS_THREADSAFE` build, the caller must be in a request on this `JSContext`.
`obj`	`JS::HandleObject` or `JSObject *`	The object on which to create the new property.
`index`	`uint32_t`	The index of the property to define.
`value`	`JS::HandleValue` or `JS::HandleObject` or `JS::HandleString` or `int32_t` or `uint32_t` or `double` or `jsval`	Initial value to assign to the property.
`getter`	`JSNative` or `JSPropertyOp`	`getProperty` method for retrieving the current property value.
`setter`	`JSNative` or `JSStrictPropertyOp`	`setProperty` method for specifying a new property value.
`flags`	`unsigned`	Property attributes. Obsolete since JSAPI 32

Description

JS_DefineElement defines a numeric property for a specified object, obj.

index is the index of the element being defined. value is one of JS::Value, JSObject, JSString, int32_t, uint32_t, or double that defines the property's initial value. getter and setter identify the getProperty and setProperty methods for the property, respectively. If you pass NULL values for these entries, JS_DefineElement assigns the default getProperty and setProperty methods to this element.

Obsolete since JSAPI 32 flags contains the property attributes to set for the new property.

On success, JS_DefineElement returns true. Otherwise it returns false.

Obsolete since JSAPI 32.

While you can assign a setProperty method to a property and set flags to JSPROP_READONLY, the setter method will not be called on this property.

Syntax

Description

See Also