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This article covers features introduced in SpiderMonkey 45
Determine whether a JavaScript object has a specified own property.
Syntax
bool
JS_HasOwnProperty(JSContext* cx, HandleObject obj, const char* name,
bool* foundp)
bool
JS_HasOwnPropertyById(JSContext* cx, HandleObject obj, HandleId id,
bool* foundp)
| Name | Type | Description |
|---|---|---|
cx |
JSContext * |
A context. Requires request. In a JS_THREADSAFE build, the caller must be in a request on this JSContext. |
obj |
JS::HandleObject |
Object to search on for the property. |
name or id |
const char * or JS::HandleId |
Name of the property to look up. |
foundp |
bool * |
Non-null pointer to a variable of type bool. On success, JS_HasOwnProperty stores true in this variable if obj has an own property with the given name, and false if not. |
Description
JS_HasOwnProperty searches an object, obj, for an own property with the specified name. It behaves like the JavaScript expression Object.hasOwnProperty(obj, name). JS_HasOwnPropertyById is the same but takes a JS::HandleId for the property name.
If the property exists, this function sets *foundp to true and returns true.
If the object obj has no such property, the function sets *foundp to false and returns true (to indicate that no error occurred).
If an error occurs during the search, the function returns false, and the value of *foundp is undefined.