jquery-deparam: deparam function separated from jQuery BBQ v1.3pre by Ben Alman http://benalman.com/projects/jquery-bbq-plugin/

jquery-deparam.js

/*jslint browser: true, ass: true, eqeq: true, forin: true, newcap: true, nomen: true, plusplus: true, regexp: true, unparam: true, sloppy: true, todo: true, vars: true, white: true */
/*!
 * jquery-deparam: deparam function separated from jQuery BBQ v1.3pre by Ben Alman
 * http://benalman.com/projects/jquery-bbq-plugin/
 * 
 * Copyright (c) 2010 "Cowboy" Ben Alman
 * Dual licensed under the MIT and GPL licenses.
 * http://benalman.com/about/license/
 */
// Project Home - http://benalman.com/projects/jquery-bbq-plugin/
// GitHub       - http://github.com/cowboy/jquery-bbq/
// 
// About: License
// 
// Copyright (c) 2010 "Cowboy" Ben Alman,
// Dual licensed under the MIT and GPL licenses.
// http://benalman.com/about/license/
(function($){
	$.deparam = function( params, coerce ) {
		var obj = {},
			coerce_types = { 'true': !0, 'false': !1, 'null': null };

		// Iterate over all name=value pairs.
		$.each( params.replace( /\+/g, ' ' ).split( '&' ), function(j,v){
			var param = v.split( '=' ),
				key = decodeURIComponent( param[0] ),
				val,
				cur = obj,
				i = 0,

				// If key is more complex than 'foo', like 'a[]' or 'a[b][c]', split it
				// into its component parts.
				keys = key.split( '][' ),
				keys_last = keys.length - 1;

			// If the first keys part contains [ and the last ends with ], then []
			// are correctly balanced.
			if ( /\[/.test( keys[0] ) && /\]$/.test( keys[ keys_last ] ) ) {
				// Remove the trailing ] from the last keys part.
				keys[ keys_last ] = keys[ keys_last ].replace( /\]$/, '' );

				// Split first keys part into two parts on the [ and add them back onto
				// the beginning of the keys array.
				keys = keys.shift().split('[').concat( keys );

				keys_last = keys.length - 1;
			} else {
				// Basic 'foo' style key.
				keys_last = 0;
			}

			// Are we dealing with a name=value pair, or just a name?
			if ( param.length === 2 ) {
				val = decodeURIComponent( param[1] );

				// Coerce values.
				if ( coerce ) {
					val = val && !isNaN(val)            ? +val              // number
						: val === 'undefined'             ? undefined         // undefined
						: coerce_types[val] !== undefined ? coerce_types[val] // true, false, null
						: val;                                                // string
				}

				if ( keys_last ) {
					// Complex key, build deep object structure based on a few rules:
					// * The 'cur' pointer starts at the object top-level.
					// * [] = array push (n is set to array length), [n] = array if n is
					//   numeric, otherwise object.
					// * If at the last keys part, set the value.
					// * For each keys part, if the current level is undefined create an
					//   object or array based on the type of the next keys part.
					// * Move the 'cur' pointer to the next level.
					// * Rinse & repeat.
					for ( ; i <= keys_last; i++ ) {
						key = keys[i] === '' ? cur.length : keys[i];
						cur = cur[key] = i < keys_last
							? cur[key] || ( keys[i+1] && isNaN( keys[i+1] ) ? {} : [] )
							: val;
					}

				} else {
					// Simple key, even simpler rules, since only scalars and shallow
					// arrays are allowed.

					if ( $.isArray( obj[key] ) ) {
						// val is already an array, so push on the next value.
						obj[key].push( val );

					} else if ( obj[key] !== undefined ) {
						// val isn't an array, but since a second value has been specified,
						// convert val into an array.
						obj[key] = [ obj[key], val ];

					} else {
						// val is a scalar.
						obj[key] = val;
					}
				}

			} else if ( key ) {
				// No value was defined, so set something meaningful.
				obj[key] = coerce
					? undefined
					: '';
			}
		});

		return obj;
	};
})(jQuery);