---
layout: page
title: "JavaScript call_user_func function"
comments: true
sharing: true
footer: true
alias:
- /functions/view/call_user_func:363
- /functions/view/call_user_func
- /functions/view/363
- /functions/call_user_func:363
- /functions/363
---
<!-- Generated by Rakefile:build -->
A JavaScript equivalent of PHP's call_user_func

{% codeblock funchand/call_user_func.js lang:js https://raw.github.com/kvz/phpjs/master/functions/funchand/call_user_func.js raw on github %}
function call_user_func (cb) {
  // From: http://phpjs.org/functions
  // +   original by: Brett Zamir (http://brett-zamir.me)
  // +   improved by: Diplom@t (http://difane.com/)
  // +   improved by: Brett Zamir (http://brett-zamir.me)
  // *     example 1: call_user_func('isNaN', 'a');
  // *     returns 1: true
  var func;

  if (typeof cb === 'string') {
    func = (typeof this[cb] === 'function') ? this[cb] : func = (new Function(null, 'return ' + cb))();
  }
  else if (Object.prototype.toString.call(cb) === '[object Array]') {
    func = (typeof cb[0] === 'string') ? eval(cb[0] + "['" + cb[1] + "']") : func = cb[0][cb[1]];
  }
  else if (typeof cb === 'function') {
    func = cb;
  }

  if (typeof func !== 'function') {
    throw new Error(func + ' is not a valid function');
  }

  var parameters = Array.prototype.slice.call(arguments, 1);
  return (typeof cb[0] === 'string') ? func.apply(eval(cb[0]), parameters) : (typeof cb[0] !== 'object') ? func.apply(null, parameters) : func.apply(cb[0], parameters);
}
{% endcodeblock %}

 - [Raw function on GitHub](https://github.com/kvz/phpjs/blob/master/functions/funchand/call_user_func.js)

Please note that php.js uses JavaScript objects as substitutes for PHP arrays, they are 
the closest match to this hashtable-like data structure. 

Please also note that php.js offers community built functions and goes by the 
[McDonald's Theory](https://medium.com/what-i-learned-building/9216e1c9da7d). We'll put online 
functions that are far from perfect, in the hopes to spark better contributions. 
Do you have one? Then please just: 

 - [Edit on GitHub](https://github.com/kvz/phpjs/edit/master/functions/funchand/call_user_func.js)

### Example 1
This code
{% codeblock lang:js example %}
call_user_func('isNaN', 'a');
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
true
{% endcodeblock %}


### Other PHP functions in the funchand extension
{% render_partial _includes/custom/funchand.html %}