Kątowy odpowiednik jQuery $. mapa?

if (!Array.prototype.map) {

 Array.prototype.map = function(callback, thisArg) { var T, A, k; if (this == null) {

 throw new TypeError(" this is null or not defined");

 }// 1. Let O be the result of calling ToObject passing the |this| value as the argument.

 var O = Object(this);// 2. Let lenValue be the result of calling the Get internal method of O with the argument "length".

// 3. Let len be ToUint32(lenValue).

 var len = O.length >>> 0;// 4. If IsCallable(callback) is false, throw a TypeError exception.

// See: [url=http://es5.github.com/#x9.11]http://es5.github.com/#x9.11[/url]

 if (typeof callback !== "function") {

 throw new TypeError(callback + " is not a function");

 }// 5. If thisArg was supplied, let T be thisArg; else let T be undefined.

 if (thisArg) {

 T = thisArg;

 }// 6. Let A be a new array created as if by the expression new Array(len) where Array is

// the standard built-in constructor with that name and len is the value of len.

 A = new Array(len);// 7. Let k be 0

 k = 0;// 8. Repeat, while k < len

 while(k < len) { var kValue, mappedValue;// a. Let Pk be ToString(k).

// This is implicit for LHS operands of the in operator

// b. Let kPresent be the result of calling the HasProperty internal method of O with argument Pk.

// This step can be combined with c

// c. If kPresent is true, then

 if (k in O) {// i. Let kValue be the result of calling the Get internal method of O with argument Pk.

 kValue = O[ k ];// ii. Let mappedValue be the result of calling the Call internal method of callback

// with T as the this value and argument list containing kValue, k, and O.

 mappedValue = callback.call(T, kValue, k, O);// iii. Call the DefineOwnProperty internal method of A with arguments

// Pk, Property Descriptor {Value: mappedValue, : true, Enumerable: true, Configurable: true},

// and false.// In browsers that support Object.defineProperty, use the following:

// Object.defineProperty(A, Pk, { value: mappedValue, writable: true, enumerable: true, configurable: true });// For best browser support, use the following:

 A[ k ] = mappedValue;

 }

// d. Increase k by 1.

 k++;

 }// 9. return A

 return A;

 }; 

}

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