peerjs/lib/util.js

var util = {
  
  chromeCompatible: true,
  firefoxCompatible: false,
  chromeVersion: 26,
  firefoxVersion: 22,

  debug: false,
  browserisms: '',
  
  inherits: function(ctor, superCtor) {
    ctor.super_ = superCtor;
    ctor.prototype = Object.create(superCtor.prototype, {
      constructor: {
        value: ctor,
        enumerable: false,
        writable: true,
        configurable: true
      }
    });
  },
  extend: function(dest, source) {
    for(var key in source) {
      if(source.hasOwnProperty(key)) {
        dest[key] = source[key];
      }
    }
    return dest;
  },
  pack: BinaryPack.pack,
  unpack: BinaryPack.unpack,
  randomPort: function() {
    return Math.round(Math.random() * 60535) + 5000;
  },
  
  log: function () {
    if (util.debug) {
      var err = false;
      var copy = Array.prototype.slice.call(arguments);
      copy.unshift('PeerJS: ');
      for (var i = 0, l = copy.length; i < l; i++){
        if (copy[i] instanceof Error) {
          copy[i] = '(' + copy[i].name + ') ' + copy[i].message;
          err = true;
        }
      }
      err ? console.error.apply(console, copy) : console.log.apply(console, copy);
    }
  },

  setZeroTimeout: (function(global) {
    var timeouts = [];
    var messageName = 'zero-timeout-message';

    // Like setTimeout, but only takes a function argument.	 There's
    // no time argument (always zero) and no arguments (you have to
    // use a closure).
    function setZeroTimeoutPostMessage(fn) {
      timeouts.push(fn);
      global.postMessage(messageName, '*');
    }		

    function handleMessage(event) {
      if (event.source == global && event.data == messageName) {
        if (event.stopPropagation) {
          event.stopPropagation();
        }
        if (timeouts.length) {
          timeouts.shift()();
        }
      }
    }
    if (global.addEventListener) {
      global.addEventListener('message', handleMessage, true);
    } else if (global.attachEvent) {
      global.attachEvent('onmessage', handleMessage);
    }
    return setZeroTimeoutPostMessage;
  }(this)),
  
  blobToArrayBuffer: function(blob, cb){
    var fr = new FileReader();
    fr.onload = function(evt) {
      cb(evt.target.result);
    };
    fr.readAsArrayBuffer(blob);
  },
  blobToBinaryString: function(blob, cb){
    var fr = new FileReader();
    fr.onload = function(evt) {
      cb(evt.target.result);
    };
    fr.readAsBinaryString(blob);
  },
  binaryStringToArrayBuffer: function(binary) {
    var byteArray = new Uint8Array(binary.length);
    for (var i = 0; i < binary.length; i++) {
      byteArray[i] = binary.charCodeAt(i) & 0xff;
    }
    return byteArray.buffer;
  },
  randomToken: function () {
    return Math.random().toString(36).substr(2);
  },
  isBrowserCompatible: function() {
    var c, f;
    if (this.chromeCompatible) {
      if ((c = navigator.userAgent.split('Chrome/')) && c.length > 1) {
        // Get version #.
        var v = c[1].split('.')[0];
        return parseInt(v) >= this.chromeVersion;
      }
    }
    if (this.firefoxCompatible) {
      if ((f = navigator.userAgent.split('Firefox/')) && f.length > 1) {
        // Get version #.
        var v = f[1].split('.')[0];
        return parseInt(v) >= this.firefoxVersion;
      }
    }
    return false;
  }
};