socket.io/lib/util.js

var global = require('global');

/**
 * Status of page load.
 */

var pageLoaded = false;

/**
 * Inheritance.
 *
 * @param {Function} ctor a
 * @param {Function} ctor b
 * @api private
 */

exports.inherits = function inherits (a, b) {
  function c () { }
  c.prototype = b.prototype;
  a.prototype = new c;
};

/**
 * Object.keys
 */

exports.keys = Object.keys || function (obj) {
  var ret = [];
  var has = Object.prototype.hasOwnProperty;

  for (var i in obj) {
    if (has.call(obj, i)) {
      ret.push(i);
    }
  }

  return ret;
};

/**
 * Adds an event.
 *
 * @api private
 */

exports.on = function (element, event, fn, capture) {
  if (element.attachEvent) {
    element.attachEvent('on' + event, fn);
  } else if (element.addEventListener) {
    element.addEventListener(event, fn, capture);
  }
};

/**
 * Load utility.
 *
 * @api private
 */

exports.load = function (fn) {
  if (global.document && document.readyState === 'complete' || pageLoaded) {
    return fn();
  }

  exports.on(global, 'load', fn, false);
};

/**
 * Change the internal pageLoaded value.
 */

if ('undefined' != typeof window) {
  exports.load(function () {
    pageLoaded = true;
  });
}

/**
 * JSON parse.
 *
 * @see Based on jQuery#parseJSON (MIT) and JSON2
 * @api private
 */

var rvalidchars = /^[\],:{}\s]*$/;
var rvalidescape = /\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g;
var rvalidtokens = /"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g;
var rvalidbraces = /(?:^|:|,)(?:\s*\[)+/g;
var rtrimLeft = /^\s+/;
var rtrimRight = /\s+$/;

exports.parseJSON = function (data) {
  if ('string' != typeof data || !data) {
    return null;
  }

  data = data.replace(rtrimLeft, '').replace(rtrimRight, '');

  // Attempt to parse using the native JSON parser first
  if (global.JSON && JSON.parse) {
    return JSON.parse(data);
  }

  if (rvalidchars.test(data.replace(rvalidescape, '@')
      .replace(rvalidtokens, ']')
      .replace(rvalidbraces, ''))) {
    return (new Function('return ' + data))();
  }
};

/**
 * UA / engines detection namespace.
 *
 * @namespace
 */

exports.ua = {};

/**
 * Detect webkit.
 *
 * @api private
 */

exports.ua.webkit = 'undefined' != typeof navigator &&
  /webkit/i.test(navigator.userAgent);

/**
 * Detect gecko.
 *
 * @api private
 */

exports.ua.gecko = 'undefined' != typeof navigator &&
  /gecko/i.test(navigator.userAgent);

/**
 * Detect android;
 */

exports.ua.android = 'undefined' != typeof navigator &&
  /android/i.test(navigator.userAgent);

/**
 * Detect iOS.
 */

exports.ua.ios = 'undefined' != typeof navigator &&
  /^(iPad|iPhone|iPod)$/.test(navigator.platform);
exports.ua.ios6 = exports.ua.ios && /OS 6_/.test(navigator.userAgent);

/**
 * Detect Chrome Frame.
 */

exports.ua.chromeframe = Boolean(global.externalHost);

/**
 * Compiles a querystring
 *
 * @param {Object}
 * @api private
 */

exports.qs = function (obj) {
  var str = '';

  for (var i in obj) {
    if (obj.hasOwnProperty(i)) {
      if (str.length) str += '&';
      str += encodeURIComponent(i) + '=' + encodeURIComponent(obj[i]);
    }
  }

  return str;
};

/**
 * Parses a simple querystring.
 *
 * @param {String} qs
 * @api private
 */

exports.qsParse = function(qs){
  var qry = {};
  var pairs = qs.split('&');
  for (var i = 0, l = pairs.length; i < l; i++) {
    var pair = pairs[i].split('=');
    qry[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
  }
  return qry;
};