can-deparam/can-deparam.js

Deserialize a query string into an array or object.

"use strict";
var namespace = require("can-namespace");

var digitTest = /^\d+$/,
	keyBreaker = /([^\[\]]+)|(\[\])/g,
	paramTest = /([^?#]*)(#.*)?$/,
	entityRegex = /%([^0-9a-f][0-9a-f]|[0-9a-f][^0-9a-f]|[^0-9a-f][^0-9a-f])/i,
	startChars = {"#": true,"?": true},
	prep = function (str) {
		if (startChars[str.charAt(0)] === true) {
			str = str.substr(1);
		}
		str = str.replace(/\+/g, ' ');

		try {
			return decodeURIComponent(str);
		}
		catch (e) {
			return decodeURIComponent(str.replace(entityRegex, function(match, hex) {
				return '%25' + hex;
			}));
		}
	};

function isArrayLikeName(name) {
	return digitTest.test(name) || name === '[]';
}


function idenity(value){ return value; }

module.exports = namespace.deparam = function (params, valueDeserializer) {
	valueDeserializer = valueDeserializer || idenity;
	var data = {}, pairs, lastPart;
	if (params && paramTest.test(params)) {
		pairs = params.split('&');
		pairs.forEach(function (pair) {
			var parts = pair.split('='),
				key = prep(parts.shift()),
				value = prep(parts.join('=')),
				current = data;
			if (key) {
				parts = key.match(keyBreaker);
				for (var j = 0, l = parts.length - 1; j < l; j++) {
					var currentName = parts[j],
						nextName = parts[j + 1],
						currentIsArray = isArrayLikeName(currentName) && current instanceof Array;
					if (!current[currentName]) {
						if(currentIsArray) {
							current.push( isArrayLikeName(nextName) ? [] : {} );
						} else {
							// If what we are pointing to looks like an `array`
							current[currentName] = isArrayLikeName(nextName) ? [] : {};
						}

					}
					if(currentIsArray) {
						current = current[current.length - 1];
					} else {
						current = current[currentName];
					}

				}
				lastPart = parts.pop();
				if ( isArrayLikeName(lastPart) ) {
					current.push(valueDeserializer(value));
				} else {
					current[lastPart] = valueDeserializer(value);
				}
			}
		});
	}
	return data;
};