JS_DeleteProperty 编辑

Removes a specified property from an object.

Syntax

bool
JS_DeleteProperty(JSContext *cx, JS::HandleObject obj, const char *name);

bool
JS_DeletePropertyById(JSContext *cx, JS::HandleObject obj, jsid id); // Added in SpiderMonkey 1.8.1

// Added in SpiderMonkey 45

bool
JS_DeleteProperty(JSContext *cx, JS::HandleObject obj, const char *name,
                  JS::ObjectOpResult &result);

bool
JS_DeletePropertyById(JSContext *cx, JS::HandleObject obj, JS::HandleId id,
                      JS::ObjectOpResult &result);

bool
JS_DeleteUCProperty(JSContext *cx, JS::HandleObject obj, const char16_t *name, size_t namelen,
                    JS::ObjectOpResult &result);

Description

JS_DeleteProperty removes a specified property, name, from an object, obj. JS_DeletePropertyById is the same but takes a jsid for the property name. These functions are identical to JS_DeleteProperty2 and JS_DeletePropertyById2 except that they do not have an out parameter.

First, a property lookup is performed. Then one of the following cases applies:

• If obj has no property with the given name or id, or if obj inherits the specified property from its prototype, then obj's JSClass.delProperty hook is called. No property is deleted, but this is not an error.
• If obj has the specified property but it is permanent, nothing happens. No property is deleted, but this is not an error.
• Otherwise obj has a non-permanent own property with the given name or id. In this case, obj's JSClass.delProperty hook is called. If the hook returns false, the error is propagated. Otherwise, if obj is not configurable, an error is raised. Otherwise, the property is removed.

These functions return true on success, regardless of whether a property was actually deleted, and false on error or exception.

(In JavaScript 1.2 and earlier, attempting to delete a permanent property caused an error. There is no longer any way to get this behavior.)

Internally, property deletion is implemented by the JSObjectOps.deleteProperty callback.

To remove all properties from an object, call JS_ClearScope.

See Also

• MXR ID Search for JS_DeleteProperty
• MXR ID Search for JS_DeletePropertyById
• JS_DeleteProperty2
• JS_DeletePropertyById2
• bug 461163
• bug 1113369 -- added result parameter and JS_DeleteUCProperty