polyfill.js

// This file exists for testing purposes but can also be used as a reference for polyfilling non-ES5 environments.
// ref: https://github.com/inexorabletash/polyfill/blob/master/es5.js (public domain)

// ES5 15.2.3.5 Object.create ( O [, Properties] )
if (typeof Object.create !== "function") {
  Object.create = function (prototype, properties) {
    if (typeof prototype !== "object") { throw TypeError(); }
    function Ctor() {}
    Ctor.prototype = prototype;
    var o = new Ctor();
    if (prototype) { o.constructor = Ctor; }
    if (properties !== undefined) {
      if (properties !== Object(properties)) { throw TypeError(); }
      Object.defineProperties(o, properties);
    }
    return o;
  };
}

// ES 15.2.3.6 Object.defineProperty ( O, P, Attributes )
// Partial support for most common case - getters, setters, and values
(function() {
  if (!Object.defineProperty ||
      !(function () { try { Object.defineProperty({}, 'x', {}); return true; } catch (e) { return false; } } ())) {
    var orig = Object.defineProperty;
    Object.defineProperty = function (o, prop, desc) {
      // In IE8 try built-in implementation for defining properties on DOM prototypes.
      if (orig) { try { return orig(o, prop, desc); } catch (e) {} }

      if (o !== Object(o)) { throw TypeError("Object.defineProperty called on non-object"); }
      if (Object.prototype.__defineGetter__ && ('get' in desc)) {
        Object.prototype.__defineGetter__.call(o, prop, desc.get);
      }
      if (Object.prototype.__defineSetter__ && ('set' in desc)) {
        Object.prototype.__defineSetter__.call(o, prop, desc.set);
      }
      if ('value' in desc) {
        o[prop] = desc.value;
      }
      return o;
    };
  }
}());

// ES 15.2.3.7 Object.defineProperties ( O, Properties )
if (typeof Object.defineProperties !== "function") {
  Object.defineProperties = function (o, properties) {
    if (o !== Object(o)) { throw TypeError("Object.defineProperties called on non-object"); }
    var name;
    for (name in properties) {
      if (Object.prototype.hasOwnProperty.call(properties, name)) {
        Object.defineProperty(o, name, properties[name]);
      }
    }
    return o;
  };
}

// ES5 15.2.3.14 Object.keys ( O )
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/keys
if (!Object.keys) {
  Object.keys = function (o) {
    if (o !== Object(o)) { throw TypeError('Object.keys called on non-object'); }
    var ret = [], p;
    for (p in o) {
      if (Object.prototype.hasOwnProperty.call(o, p)) {
        ret.push(p);
      }
    }
    return ret;
  };
}

// ES5 15.4.3.2 Array.isArray ( arg )
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/isArray
if (!Array.isArray)
  Array.isArray = function (o) { return Boolean(o && Object.prototype.toString.call(Object(o)) === '[object Array]'); };

// ES5 15.4.4.14 Array.prototype.indexOf ( searchElement [ , fromIndex ] )
// From https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/indexOf
if (!Array.prototype.indexOf) {
  Array.prototype.indexOf = function (searchElement /*, fromIndex */) {
    if (this === void 0 || this === null) { throw TypeError(); }

    var t = Object(this);
    var len = t.length >>> 0;
    if (len === 0) { return -1; }

    var n = 0;
    if (arguments.length > 0) {
      n = Number(arguments[1]);
      if (isNaN(n)) {
        n = 0;
      } else if (n !== 0 && n !== (1 / 0) && n !== -(1 / 0)) {
        n = (n > 0 || -1) * Math.floor(Math.abs(n));
      }
    }

    if (n >= len) { return -1; }

    var k = n >= 0 ? n : Math.max(len - Math.abs(n), 0);

    for (; k < len; k++) {
      if (k in t && t[k] === searchElement) {
        return k;
      }
    }
    return -1;
  };
}

// ES5 15.4.4.18 Array.prototype.forEach ( callbackfn [ , thisArg ] )
// From https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/forEach
if (!Array.prototype.forEach) {
  Array.prototype.forEach = function (fun /*, thisp */) {
    if (this === void 0 || this === null) { throw TypeError(); }

    var t = Object(this);
    var len = t.length >>> 0;
    if (typeof fun !== "function") { throw TypeError(); }

    var thisp = arguments[1], i;
    for (i = 0; i < len; i++) {
      if (i in t) {
        fun.call(thisp, t[i], i, t);
      }
    }
  };
}


// ES5 15.4.4.19 Array.prototype.map ( callbackfn [ , thisArg ] )
// From https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/Map
if (!Array.prototype.map) {
  Array.prototype.map = function (fun /*, thisp */) {
    if (this === void 0 || this === null) { throw TypeError(); }

    var t = Object(this);
    var len = t.length >>> 0;
    if (typeof fun !== "function") { throw TypeError(); }

    var res = []; res.length = len;
    var thisp = arguments[1], i;
    for (i = 0; i < len; i++) {
      if (i in t) {
        res[i] = fun.call(thisp, t[i], i, t);
      }
    }

    return res;
  };
}

// ES5 15.4.4.20 Array.prototype.filter ( callbackfn [ , thisArg ] )
// From https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/Filter
if (!Array.prototype.filter) {
  Array.prototype.filter = function (fun /*, thisp */) {
    if (this === void 0 || this === null) { throw TypeError(); }

    var t = Object(this);
    var len = t.length >>> 0;
    if (typeof fun !== "function") { throw TypeError(); }

    var res = [];
    var thisp = arguments[1], i;
    for (i = 0; i < len; i++) {
      if (i in t) {
        var val = t[i]; // in case fun mutates this
        if (fun.call(thisp, val, i, t)) {
          res.push(val);
        }
      }
    }

    return res;
  };
}