JavaScript method_exists

Checks if the class method exists

function method_exists (obj, method) {
    // Checks if the class method exists  
    // 
    // version: 1109.2015
    // discuss at: http://phpjs.org/functions/method_exists    // +   original by: Brett Zamir (http://brett-zamir.me)
    // *     example 1: function class_a() {this.meth1 = function () {return true;}};
    // *     example 1: var instance_a = new class_a();
    // *     example 1: method_exists(instance_a, 'meth1');
    // *     returns 1: true    // *     example 2: function class_a() {this.meth1 = function () {return true;}};
    // *     example 2: var instance_a = new class_a();
    // *     example 2: method_exists(instance_a, 'meth2');
    // *     returns 2: false
    if (typeof obj === 'string') {        return this.window[obj] && typeof this.window[obj][method] === 'function';
    }
 
    return typeof obj[method] === 'function';
}

external links: original PHP docs | raw js source

Examples

» Example 1

Running

1
2
3

function class_a() {this.meth1 = function () {return true;}};
var instance_a = new class_a();
method_exists(instance_a, 'meth1');

Should return

true

» Example 2

Running

1
2
3

function class_a() {this.meth1 = function () {return true;}};
var instance_a = new class_a();
method_exists(instance_a, 'meth2');

Should return

false

Dependencies

No dependencies, you can use this function standalone.

Open syntax issues

php.js uses JsLint to help us keep our code consistent and prevent some common bugs.

Eventually we want all code to pass or at least take into consideration most fixes suggested by JsLint, following this JsLint configuration we’ve decided on.

Authors

Thanks to the following developers, you get to have method_exists goodness in JavaScript.

Brett Zamir ( original )

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Use:

[CODE]
your_stuff('here');
[/CODE]

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