array-enhancements
Version:
Many helpful functions for javascript Arrays
263 lines (222 loc) • 8.86 kB
JavaScript
(function () {
"use strict";
// from mozilla
if (!Array.prototype.reduce) {
/**
* Applies iteratively the callback function to the elements of the array, so as to reduce the array to a single value.
*/
Array.prototype.reduce = function reduce(accumulator) {
var i, l = this.length, curr;
if (typeof accumulator !== "function") { // ES5 : "If IsCallable(callbackfn) is false, throw a TypeError exception."
throw new TypeError("First argument is not callable");
}
if ((l === 0 || l === null) && (arguments.length <= 1)) {// == on purpose to test 0 and false.
throw new TypeError("Array length is 0 and no second argument");
}
if (arguments.length <= 1) {
curr = this[0]; // Increase i to start searching the secondly defined element in the array
i = 1; // start accumulating at the second element
} else {
curr = arguments[1];
}
for (i = i || 0; i < l; ++i) {
if (i in this) {
curr = accumulator.call(undefined, curr, this[i], i, this);
}
}
return curr;
};
}
// from mozilla
if (!Array.prototype.filter) {
/**
* Iterates over each value in the array passing them to the callback function. If the callback function returns true, the current value from array is returned into the result array.
*/
Array.prototype.filter = function (fun /*, thisp */) {
if (this === null) {
throw new TypeError();
}
var t = Object(this),
len = t.length >>> 0,
res,
thisp,
i,
val;
if ('function' !== typeof fun) {
throw new TypeError();
}
res = [];
thisp = arguments[1];
for (i = 0; i < len; i++) {
if (i in t) {
val = t[i]; // in case fun mutates this
if (fun.call(thisp, val, i, t)) {
res.push(val);
}
}
}
return res;
};
}
// from mozilla
if ('function' !== typeof Array.prototype.reduceRight) {
Array.prototype.reduceRight = function (callback, opt_initialValue) {
if (null === this || 'undefined' === typeof this) {
// At the moment all modern browsers, that support strict mode, have
// native implementation of Array.prototype.reduceRight. For instance,
// IE8 does not support strict mode, so this check is actually useless.
throw new TypeError('Array.prototype.reduceRight called on null or undefined');
}
if ('function' !== typeof callback) {
throw new TypeError(callback + ' is not a function');
}
var length = this.length >>> 0,
index,
value,
isValueSet = false;
if (1 < arguments.length) {
value = opt_initialValue;
isValueSet = true;
}
for (index = length - 1; -1 < index; --index) {
if (this.hasOwnProperty(index)) {
if (isValueSet) {
value = callback(value, this[index], index, this);
} else {
value = this[index];
isValueSet = true;
}
}
}
if (!isValueSet) {
throw new TypeError('Reduce of empty array with no initial value');
}
return value;
};
}
// from mozilla
if (!Array.prototype.some) {
Array.prototype.some = function (fun /*, thisp */) {
if (this === null) {
throw new TypeError();
}
if (typeof fun !== "function") {
throw new TypeError();
}
var t = Object(this),
len = t.length >>> 0,
thisp = arguments[1],
i;
for (i = 0; i < len; i++) {
if (i in t && fun.call(thisp, t[i], i, t)) {
return true;
}
}
return false;
};
}
// from mozilla
if (!Array.prototype.every) {
Array.prototype.every = function (fun /*, thisp */) {
var t,
len,
i,
thisp;
if (this === null) {
throw new TypeError();
}
t = Object(this);
len = t.length >>> 0;
if (typeof fun !== 'function') {
throw new TypeError();
}
thisp = arguments[1];
for (i = 0; i < len; i++) {
if (i in t && !fun.call(thisp, t[i], i, t)) {
return false;
}
}
return true;
};
}
// from mozilla
if (!Array.prototype.forEach) {
Array.prototype.forEach = function (fn, scope) {
var i,
len;
for (i = 0, len = this.length; i < len; ++i) {
if (i in this) {
fn.call(scope, this[i], i, this);
}
}
};
}
// from mozilla
// Production steps of ECMA-262, Edition 5, 15.4.4.19
// Reference: http://es5.github.com/#x15.4.4.19
if (!Array.prototype.map) {
Array.prototype.map = function (callback, thisArg) {
var T,
A,
k,
O,
len,
kValue,
mappedValue;
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.
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).
len = O.length >>> 0;
// 4. If IsCallable(callback) is false, throw a TypeError exception.
// See: http://es5.github.com/#x9.11
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) {
// 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;
};
}
// from mozilla
if(!Array.isArray) {
Array.isArray = function (vArg) {
return Object.prototype.toString.call(vArg) === "[object Array]";
};
}
}());