parseAmpersandDelimitedKeyValuePairs.js

/* parseQueryParameters & parseFragmentIdentifiers */

var setValue = function(obj, prop, val) {
  if (!(prop in obj)) {
    obj[prop] = val;
  } else {
    if (!(obj[prop] instanceof Array)) {
      obj[prop] = [obj[prop]];
    }
    obj[prop].push(val);
  }
};

// Note: This setDeepValue function has been modified from the original
// function for performance enhancement available in this context
var setDeepValue = function (obj, props, val) {
  for (var i = 0, n = props.length - 1; i < n; ++i) {
    obj = obj[props[i]] = obj[props[i]] || {};
  }
  setValue(obj, props[i], val);
};

var parseAmpersandDelimitedKeyValuePairs = function(str /*, typeVals */) {

  if (!str) {
    return {};
  }

  var params   = {},
      pairs    = str.split('&'),
      typeVals = (arguments[1] !== false),
      re       = /^([^\[]+)(?:[\[](.*)[\]])?$/,
      pair,
      key,
      val,
      num,
      matches;

  for (var i = 0, n = pairs.length; i < n; ++i) {

    pair = pairs[i].split('=');
    key  = pair[0];
    val  = pair[1];

    if (typeof val === 'string') {
      
      val = unescape(val);
      
      // Type non-String data types
      if (typeVals === true && val !== '') {

        // Number
        if (!isNaN(val)) {
          val = Number(val);

        // Boolean true
        } else if (val.toLowerCase() === 'true') {
          val = true;

        // Boolean false
        } else if (val.toLowerCase() === 'false') {
          val = false;

        // null
        } else if (val.toLowerCase() === 'null') {
          val = null;

        // undefined (explicit)
        } else if (val.toLowerCase() === 'undefined') {
          val = undefined;
        }
      }

    // undefined (implicit)
    } else {
      val = undefined;
    }

    // Look for complex data types (arrays, objects)
    key.replace(re, function(match, key, deepProp) {
      // Complex
      if (typeof deepProp !== 'undefined' && deepProp !== '') {
        setDeepValue(params, [key].concat(deepProp.split(/\]\[/)), val);
      // Primitive
      } else {
        setValue(params, key, val);
      }
    });
  }

  return params;
};

var parseQueryParameters = function(/* url, typeVals */) {
  var url = arguments[0] || window.location.search,
      str = url.substring(url.indexOf('?') + 1);
  return parseAmpersandDelimitedKeyValuePairs(str, arguments[1]);
};

var parseFragmentIdentifiers = function(/* url, typeVals */) {
  var url = arguments[0] || window.location.hash,
      str = url.substring(url.indexOf('#') + 1);
  return parseAmpersandDelimitedKeyValuePairs(str, arguments[1]);
};

var params = parseQueryParameters();
console.dir(params);