Determine if an object is an instance of a specified
| || ||Pointer to a JS context from which to derive runtime information. Requires request. In a |
| || ||Object to test.|
| || ||Class against which to test the object.|
| || ||Optional argument vector. If non-null, report an error if |
JS_InstanceOf can be used to check whether an object obj is of a particular
JSClass. To use it this way, pass
obj is of the given class and
JS_FALSE otherwise. That is, it returns
JS_GetClass(obj) == clasp.
JS_InstanceOf can also be used in native functions to check the class of an argument when a particular class is required. To use it this way, pass the argument vector provided by the engine for
argv. When argv is non-null, JS_InstanceOf behaves as follows. If obj is of the given class, it returns
JS_TRUE. Otherwise, it returns
JS_FALSE; but if
JS_ARGV_CALLEE(argv) is a function, it also reports a
TypeError containing the function's name.
instanceof keyword, which examines
constructor properties along the prototype chain.
JS_HasInstance is similar to