---
layout: page
title: "JavaScript parse_str function"
comments: true
sharing: true
footer: true
alias:
- /functions/view/parse_str:484
- /functions/view/parse_str
- /functions/view/484
- /functions/parse_str:484
- /functions/484
---
<!-- Generated by Rakefile:build -->
A JavaScript equivalent of PHP's parse_str

{% codeblock strings/parse_str.js lang:js https://raw.github.com/kvz/phpjs/master/functions/strings/parse_str.js raw on github %}
function parse_str (str, array) {
  // From: http://phpjs.org/functions
  // +      original by: Cagri Ekin
  // +      improved by: Michael White (http://getsprink.com)
  // +       tweaked by: Jack
  // +      bugfixed by: Onno Marsman
  // + reimplemented by: stag019
  // +      bugfixed by: Brett Zamir (http://brett-zamir.me)
  // +      bugfixed by: stag019
  // +         input by: Dreamer
  // +      bugfixed by: Brett Zamir (http://brett-zamir.me)
  // +      bugfixed by: MIO_KODUKI (http://mio-koduki.blogspot.com/)
  // +         input by: Zaide (http://zaidesthings.com/)
  // +         input by: David Pesta (http://davidpesta.com/)
  // +         input by: jeicquest
  // +      improved by: Brett Zamir (http://brett-zamir.me)
  // %           note 1: When no argument is specified, will put variables in global scope.
  // %           note 1: When a particular argument has been passed, and the returned value is different parse_str of PHP. For example, a=b=c&d====c
  // %             test: skip
  // *        example 1: var arr = {};
  // *        example 1: parse_str('first=foo&second=bar', arr);
  // *        example 1: arr
  // *        returns 1: { first: 'foo', second: 'bar' }
  // *        example 2: var arr = {};
  // *        example 2: parse_str('str_a=Jack+and+Jill+didn%27t+see+the+well.', arr);
  // *        example 2: arr
  // *        returns 2: { str_a: "Jack and Jill didn't see the well." }
  // *        example 3: var abc = {3:'a'};
  // *        example 3: parse_str('abc[a][b]["c"]=def&abc[q]=t+5');
  // *        returns 3: {"3":"a","a":{"b":{"c":"def"}},"q":"t 5"}

  var strArr = String(str).replace(/^&/, '').replace(/&$/, '').split('&'),
    sal = strArr.length,
    i, j, ct, p, lastObj, obj, lastIter, undef, chr, tmp, key, value,
    postLeftBracketPos, keys, keysLen,
    fixStr = function (str) {
      return decodeURIComponent(str.replace(/\+/g, '%20'));
    };

  if (!array) {
    array = this.window;
  }

  for (i = 0; i < sal; i++) {
    tmp = strArr[i].split('=');
    key = fixStr(tmp[0]);
    value = (tmp.length < 2) ? '' : fixStr(tmp[1]);

    while (key.charAt(0) === ' ') {
      key = key.slice(1);
    }
    if (key.indexOf('\x00') > -1) {
      key = key.slice(0, key.indexOf('\x00'));
    }
    if (key && key.charAt(0) !== '[') {
      keys = [];
      postLeftBracketPos = 0;
      for (j = 0; j < key.length; j++) {
        if (key.charAt(j) === '[' && !postLeftBracketPos) {
          postLeftBracketPos = j + 1;
        }
        else if (key.charAt(j) === ']') {
          if (postLeftBracketPos) {
            if (!keys.length) {
              keys.push(key.slice(0, postLeftBracketPos - 1));
            }
            keys.push(key.substr(postLeftBracketPos, j - postLeftBracketPos));
            postLeftBracketPos = 0;
            if (key.charAt(j + 1) !== '[') {
              break;
            }
          }
        }
      }
      if (!keys.length) {
        keys = [key];
      }
      for (j = 0; j < keys[0].length; j++) {
        chr = keys[0].charAt(j);
        if (chr === ' ' || chr === '.' || chr === '[') {
          keys[0] = keys[0].substr(0, j) + '_' + keys[0].substr(j + 1);
        }
        if (chr === '[') {
          break;
        }
      }

      obj = array;
      for (j = 0, keysLen = keys.length; j < keysLen; j++) {
        key = keys[j].replace(/^['"]/, '').replace(/['"]$/, '');
        lastIter = j !== keys.length - 1;
        lastObj = obj;
        if ((key !== '' && key !== ' ') || j === 0) {
          if (obj[key] === undef) {
            obj[key] = {};
          }
          obj = obj[key];
        }
        else { // To insert new dimension
          ct = -1;
          for (p in obj) {
            if (obj.hasOwnProperty(p)) {
              if (+p > ct && p.match(/^\d+$/g)) {
                ct = +p;
              }
            }
          }
          key = ct + 1;
        }
      }
      lastObj[key] = value;
    }
  }
}
{% endcodeblock %}

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

### Example 1
This code
{% codeblock lang:js example %}
var arr = {};
parse_str('first=foo&second=bar', arr);
arr
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
{ first: 'foo', second: 'bar' }
{% endcodeblock %}

### Example 2
This code
{% codeblock lang:js example %}
var arr = {};
parse_str('str_a=Jack+and+Jill+didn%27t+see+the+well.', arr);
arr
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
{ str_a: "Jack and Jill didn't see the well." }
{% endcodeblock %}

### Example 3
This code
{% codeblock lang:js example %}
var abc = {3:'a'};
parse_str('abc[a][b]["c"]=def&abc[q]=t+5');
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
{"3":"a","a":{"b":{"c":"def"}},"q":"t 5"}
{% endcodeblock %}


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