map() Example 2
/*------------------------------------------------------------------------------
* JavaScript zArray Library
* Version 1.1
* by Nicholas C. Zakas, http://www.nczonline.net/
* Copyright (c) 2004-2005 Nicholas C. Zakas. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*------------------------------------------------------------------------------
*/
var aCheckMethods = new Array("concat", "push", "pop", "every", "some", "forEach",
"filter", "map", "indexOf", "lastIndexOf", "slice",
"splice", "shift", "unshift");
/**
* Appends any number of items onto the end of the array.
*/
Array.prototype.append = function () {
for (var i=0; i < arguments.length; i++) {
this[this.length] = arguments[i];
}
};
/**
* Creates a copy of the array and returns it.
* @return A copy of the array.
*/
Array.prototype.clone = function () /*:Array*/ {
return this.concat();
};
/**
* Determines if a given item is in the array.
* @param vItem The item to insert.
* @return True if found, false if not.
*/
Array.prototype.contains = function (vItem /*:variant*/) /*:boolean*/ {
return this.indexOf(vItem)>-1;
};
/**
* Runs a function on each item in the array and returns a result.
* Defined in Mozilla 1.8 Core JavaScript
* @param fnTest The function to run on each value.
* @param oThis The object that the function belongs to or null for a global
* function.
* @return True if the function evaluates to true for each item in the array,
* false if even one returns false.
*/
Array.prototype._every = function (fnTest /*:Function*/, oThis /*:Object*/)/*:boolean*/ {
if (this.length > 0) {
var bResult = true;
oThis = oThis || window;
oThis.__everyFunc__ = fnTest;
for (var i=0, l=this.length; i < l && bResult; i++) {
bResult = bResult && oThis.__everyFunc__(this[i], i, this);
}
oThis.__everyFunc__ = null;
return bResult;
} else {
return true; //fix(1.02): changed from false
}
};
/**
* Runs a function on each item and returns an array.
* Defined in Mozilla 1.8 Core JavaScript
* @param fnTest The function to run on each item.
* @param oThis The object that the function belongs to or null for a global
* function.
* @return An array made up of all the items that returned true for the function.
*/
Array.prototype._filter= function (fnTest /*:Function*/, oThis /*:Object*/)/*:Array*/ {
var aResult /*:Array*/ = new Array();
oThis = oThis || window;
oThis.__filterFunc__ = fnTest;
for (var i=0, l=this.length; i < l; i++) {
if (oThis.__filterFunc__(this[i], i, this)) {
aResult.push(this[i]);
}
}
oThis.__filterFunc__ = null;
return aResult;
};
/**
* Runs a function on each item in the array and returns a result.
* Defined in Mozilla 1.8 Core JavaScript
* @param fnExec The function to run on each value.
* @param oThis The object that the function belongs to or null for a global
* function.
*/
Array.prototype._forEach = function (fnExec /*:Function*/, oThis /*:Object*/) {
oThis = oThis || window;
oThis.__forEachFunc__ = fnExec;
for (var i=0, l=this.length; i < l; i++) {
oThis.__forEachFunc__(this[i], i, this);
}
oThis.__forEachFunc__ = null;
};
/**
* Returns the index of the first occurrance in the array.
* Defined in Mozilla 1.8 Core JavaScript
* @param vItem The item to locate in the array.
* @param iStart The item to start looking from (optional).
* @return The index of the item in the array if found or -1 if not found.
*/
Array.prototype._indexOf = function (vItem /*:Variant*/, iStart /*:int*/)/*:int*/ {
if (iStart == null) {
iStart = 0;
}
for (var i=iStart, l=this.length; i < l; i++) {
if (this[i] == vItem) {
return i;
}
}
return -1;
};
/**
* Inserts an item into the array at the given position.
* @param vItem The item to insert.
* @param iIndex The index to insert the item into.
*/
Array.prototype.insertAt = function (vItem /*:variant*/, iIndex /*:int*/) /*:variant*/ {
this.splice(iIndex, 0, vItem);
};
/**
* Inserts an item into the array before the given item.
* @param vItem The item to insert.
* @param vBeforeItem The item to insert before.
*/
Array.prototype.insertBefore = function (vItem /*:variant*/, vBeforeItem /*:variant*/) /*:variant*/ {
this.insertAt(vItem, this.indexOf(vBeforeItem));
};
/**
* Returns the last index of the first occurrance in the array.
* Defined in Mozilla 1.8 Core JavaScript
* @param vItem The item to locate in the array.
* @param iStart The index of the item to start at.
* @return The last index of the item in the array if found or -1 if not found.
*/
Array.prototype._lastIndexOf = function (vItem /*:Variant*/, iStart /*:int*/)/*:int*/ {
if (iStart == null || iStart >= this.length) {
iStart = this.length-1;
}
for (var i=iStart; i >= 0; i--) {
if (this[i] == vItem) {
return i;
}
}
return -1;
};
/**
* Runs a function on each item and returns an array.
* Defined in Mozilla 1.8 Core JavaScript
* @param fnExec The function to run on each item.
* @param oThis The object that the function belongs to or null for a global
* function.
* @return An array made up of all the items that returned true for the function.
*/
Array.prototype._map = function (fnExec /*:Function*/, oThis /*:Object*/)/*:Array*/ {
var aResult /*:Array*/ = new Array();
oThis = oThis || window;
oThis.__mapFunc__ = fnExec;
for (var i=0, l=this.length; i < l; i++) {
aResult.push(oThis.__mapFunc__(this[i], i, this));
}
oThis.__mapFunc__ = null;
return aResult;
};
/**
* Pops off the last item in the array and returns it.
* Defined in ECMA-262 3rd Edition.
* @return The last item in the array.
*/
Array.prototype._pop = function ()/*:variant*/ {
var oItem /*:Variant*/ = null;
if (this.length > 0) {
oItem = this[this.length-1];
this.length--;
}
return oItem;
};
/**
* Pushes any number of items onto the end of the array.
* Defined in ECMA-262 3rd Edition.
*/
Array.prototype._push = Array.prototype.append;
/**
* Removes the array item matching the given item.
* @param vItem the item to remove.
* @return The removed item.
*/
Array.prototype.remove = function (vItem /*:variant*/) /*:variant*/ {
this.removeAt(this.indexOf(vItem));
return vItem;
};
/**
* Removes the array item in the given position.
* @param iIndex The index of the item to remove.
* @return The removed item.
*/
Array.prototype.removeAt = function (iIndex /*:int*/) /*:variant*/ {
var vItem = this[iIndex];
if (vItem) {
this.splice(iIndex, 1);
}
return vItem;
};
/**
* Creates an array composed of the indicated items in the current array.
* Defined in ECMA-262 3rd Edition.
* @param iStart The first item to copy.
* @param iStop The index after the last item to copy.
* @return An array containing all items in the original array between the given
* indices.
*/
Array.prototype._slice = function (iStart /*:int*/, iStop /*:int*/)/*:Array*/ {
var aResult /*:Array*/ = new Array();
iStop = iStop || this.length;
for (var i=iStart; i < iStop; i++) {
aResult.push(this[i]);
}
return aResult;
};
/**
* Removes the first item in the array and returns it.
* Defined in ECMA-262 3rd Edition.
* @return The first item in the array.
*/
Array.prototype._shift = function ()/*:variant*/ {
var vItem = this[0];
if (vItem) {
this.splice(0,1);
}
return vItem;
};
/**
* Runs a function on each item in the array and returns a result.
* Defined in Mozilla 1.8 Core JavaScript
* @param fnTest The function to run on each value.
* @return True if the function evaluates to true for any one item, false if not.
*/
Array.prototype._some= function (fnTest /*:Function*/, oThis /*:Object*/)/*:boolean*/ {
oThis = oThis || window;
oThis.__someFunc__ = fnTest;
for (var i=0, l=this.length; i < l; i++) {
if (oThis.__someFunc__(this[i], i, this)) {
return true;
}
}
oThis.__someFunc__ = null;
return false;
};
/**
* Alters the array by removing specified items and inserting others.
* Defined in ECMA-262 3rd Edition.
* @param iIndex The index at which to begin altering the array.
* @param iLength The number of items to remove.
* @param vItem[] The items to insert in place of the removed items.
* @return An array containing all removed items.
*/
Array.prototype._splice = function (iIndex /*:int*/, iLength /*:int*/)/*:Array*/ {
var aResult /*:Array*/ = new Array();
var aRemoved /*: Array */ = new Array();
for (var i=0; i < iIndex; i++){
aResult.push(this[i]);
}
for (var i=iIndex; i < iIndex+iLength; i++) {
aRemoved.push(this[i]);
}
if (arguments.length > 2) {
for (var i=2; i < arguments.length; i++) {
aResult.push(arguments[i]);
}
}
for (var i=iIndex+iLength; i < this.length; i++) {
aResult.push(this[i]);
}
for (var i=0; i < aResult.length; i++) {
this[i] = aResult[i];
}
this.length = aResult.length;
return aRemoved;
};
/**
* Adds all the items in the array and returns the result.
* @param fnConvert An optional function to run on each item before adding.
* @param oThis The object that the function belongs to or null for a global
* function.
* @return The result of adding all of the array items together.
*/
Array.prototype.sum = function (fnConvert /*:Function*/, oThis /*:Object*/)/*:variant*/ {
if (this.length > 0) {
var vResult = null;
oThis = oThis || window;
oThis.__sumFunc__ = fnConvert || function (vVal) { return vVal; };
vResult = oThis.__sumFunc__(this[0], 0, this);
for (var i=1, l=this.length; i < l; i++) {
vResult += oThis.__sumFunc__(this[i], i, this);
}
oThis.__sumFunc__ = null;
return vResult;
} else {
return null;
}
};
/**
* Places the given items at the beginning of the array.
* Defined in ECMA-262 3rd Edition.
* @param vItem[] Items to add into the
*/
Array.prototype._unshift = function () {
var sExec = "this.splice(";
var aArgs = new Array();
for (var i=0,l=arguments.length; i < l; i++) {
aArgs.push("arguments["+i+"]");
}
eval("this.splice(0,0," + aArgs.join(",") + ")");
};
/*
* Assign the necessary methods.
*/
for (var i=0; i < aCheckMethods.length; i++) {
if(!Array.prototype[aCheckMethods[i]]) {
Array.prototype[aCheckMethods[i]] = Array.prototype["_"+aCheckMethods[i]];
}
}
map() Example 2
var aNumbers = [1, 4, 9];
var aRoots = aNumbers.map(Math.sqrt);
// aRoots is now [1, 2, 3]
// aNumbers is still [1, 4, 9]
alert(aNumbers);
alert(aRoots);
This example defines an array [1, 4, 9]
and then returns an array with the square roots of all numbers.