Object.prototype.__defineGetter__()
Warning: This feature is deprecated in favor of defining getters using the
object initializer syntax
or the Object.defineProperty()
API. While this
feature is widely implemented, it is only described in the
ECMAScript specification
because of legacy usage. This method should not be used since
better alternatives exist.
The __defineGetter__
method binds an object's property to
a function to be called when that property is looked up.
Syntax
__defineGetter__(prop, func)
Parameters
prop
-
A string containing the name of the property to bind to the given function.
func
-
A function to be bound to a lookup of the specified property.
Return value
Description
The __defineGetter__
allows a getter
to be defined on a pre-existing object.
Examples
Non-standard and deprecated way
var o = {};
o.__defineGetter__('gimmeFive', function() { return 5; });
console.log(o.gimmeFive); // 5
Standard-compliant ways
// Using the get operator
var o = { get gimmeFive() { return 5; } };
console.log(o.gimmeFive); // 5
// Using Object.defineProperty
var o = {};
Object.defineProperty(o, 'gimmeFive', {
get: function() {
return 5;
}
});
console.log(o.gimmeFive); // 5
Specifications
Specification |
---|
ECMAScript Language Specification # sec-object.prototype.__defineGetter__ |
Browser compatibility
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See also
- Polyfill of
Object.prototype.__defineGetter__
incore-js
Object.prototype.__defineSetter__()
get
operatorObject.defineProperty()
Object.prototype.__lookupGetter__()
Object.prototype.__lookupSetter__()
- JS Guide: Defining Getters and Setters
- [Blog Post] Deprecation of __defineGetter__ and __defineSetter__
- bug 647423