---
layout: page
title: "JavaScript empty function"
comments: true
sharing: true
footer: true
alias:
- /functions/view/empty:392
- /functions/view/empty
- /functions/view/392
- /functions/empty:392
- /functions/392
---
<!-- Generated by Rakefile:build -->
A JavaScript equivalent of PHP's empty

{% codeblock var/empty.js lang:js https://raw.github.com/kvz/phpjs/master/functions/var/empty.js raw on github %}
function empty (mixed_var) {
  // Checks if the argument variable is empty
  // undefined, null, false, number 0, empty string,
  // string "0", objects without properties and empty arrays
  // are considered empty
  //
  // From: http://phpjs.org/functions
  // +   original by: Philippe Baumann
  // +      input by: Onno Marsman
  // +   bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // +      input by: LH
  // +   improved by: Onno Marsman
  // +   improved by: Francesco
  // +   improved by: Marc Jansen
  // +      input by: Stoyan Kyosev (http://www.svest.org/)
  // +   improved by: Rafal Kukawski
  // *     example 1: empty(null);
  // *     returns 1: true
  // *     example 2: empty(undefined);
  // *     returns 2: true
  // *     example 3: empty([]);
  // *     returns 3: true
  // *     example 4: empty({});
  // *     returns 4: true
  // *     example 5: empty({'aFunc' : function () { alert('humpty'); } });
  // *     returns 5: false
  var undef, key, i, len;
  var emptyValues = [undef, null, false, 0, "", "0"];

  for (i = 0, len = emptyValues.length; i < len; i++) {
    if (mixed_var === emptyValues[i]) {
      return true;
    }
  }

  if (typeof mixed_var === "object") {
    for (key in mixed_var) {
      // TODO: should we check for own properties only?
      //if (mixed_var.hasOwnProperty(key)) {
      return false;
      //}
    }
    return true;
  }

  return false;
}
{% endcodeblock %}

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

### Example 1
This code
{% codeblock lang:js example %}
empty(null);
{% endcodeblock %}

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

### Example 2
This code
{% codeblock lang:js example %}
empty(undefined);
{% endcodeblock %}

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

### Example 3
This code
{% codeblock lang:js example %}
empty([]);
{% endcodeblock %}

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


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