Array.prototype

array.prototype.js

// forEach

if (typeof Array.prototype.forEach != "function") {
  Array.prototype.forEach = function (fn, context) {
    for (var k = 0, length = this.length; k < length; k++) {
      if (typeof fn === "function") {
        fn.call(context, this[k], k, this);
      }
    }
  };
}

// map
if (typeof Array.prototype.map != "function") {
  Array.prototype.map = function (fn, context) {
    var arr = [];
    if (typeof fn === "function") {
      for (var k = 0, length = this.length; k < length; k++)           {      
         arr.push(fn.call(context, this[k], k, this));
      }
    }
    return arr;
  };
}

// filter
if (typeof Array.prototype.filter != "function") {
  Array.prototype.filter = function (fn, context) {
    var arr = [];
    if (typeof fn === "function") {
       for (var k = 0, length = this.length; k < length; k++) {
          fn.call(context, this[k], k, this) && arr.push(this[k]);
       }
    }
    return arr;
  };
}

// some
if (typeof Array.prototype.some != "function") {
  Array.prototype.some = function (fn, context) {
    var passed = false;
    if (typeof fn === "function") {
      for (var k = 0, length = this.length; k < length; k++) {
          if (passed === true) break;
          passed = !!fn.call(context, this[k], k, this);
      }
    }
    return passed;
  };
}

// every
if (typeof Array.prototype.every != "function") {
  Array.prototype.every = function (fn, context) {
    var passed = true;
    if (typeof fn === "function") {
       for (var k = 0, length = this.length; k < length; k++) {
          if (passed === false) break;
          passed = !!fn.call(context, this[k], k, this);
      }
    }
    return passed;
  };
}

// indexOf
if (typeof Array.prototype.indexOf != "function") {
  Array.prototype.indexOf = function (searchElement, fromIndex) {
    var index = -1;
    fromIndex = fromIndex * 1 || 0;
      
    for (var k = 0, length = this.length; k < length; k++) {
      if (k >= fromIndex && this[k] === searchElement) {
          index = k;
          break;
      }
    }
    return index;
  };
}

// lastIndexOf
if (typeof Array.prototype.lastIndexOf != "function") {
  Array.prototype.lastIndexOf = function (searchElement, fromIndex) {
    var index = -1, length = this.length;
    fromIndex = fromIndex * 1 || length - 1;
    
    for (var k = length - 1; k > -1; k-=1) {
        if (k <= fromIndex && this[k] === searchElement) {
            index = k;
            break;
        }
    }
    return index;
  };
}