analytics/webcontent/dojo17/dojox/lang/functional/reversed.js

define("dojox/lang/functional/reversed", ["dojo/_base/lang", "dojo/_base/window" ,"./lambda"], 
	function(lang, win, df){
// This module adds high-level functions and related constructs:
//	- reversed versions of array-processing functions similar to standard JS functions

// Notes:
//	- this module provides reversed versions of standard array-processing functions:
//		forEachRev, mapRev, filterRev

// Defined methods:
//	- take any valid lambda argument as the functional argument
//	- operate on dense arrays
//	- take a string as the array argument

/*=====
	var df = dojox.lang.functional;
 =====*/
	lang.mixin(df, {
		// JS 1.6 standard array functions, which can take a lambda as a parameter.
		// Consider using dojo._base.array functions, if you don't need the lambda support.
		filterRev: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary: creates a new array with all elements that pass the test
			//	implemented by the provided function.
			if(typeof a == "string"){ a = a.split(""); }
			o = o || win.global; f = df.lambda(f);
			var t = [], v, i = a.length - 1;
			for(; i >= 0; --i){
				v = a[i];
				if(f.call(o, v, i, a)){ t.push(v); }
			}
			return t;	// Array
		},
		forEachRev: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary: executes a provided function once per array element.
			if(typeof a == "string"){ a = a.split(""); }
			o = o || win.global; f = df.lambda(f);
			for(var i = a.length - 1; i >= 0; f.call(o, a[i], i, a), --i);
		},
		mapRev: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary: creates a new array with the results of calling
			//	a provided function on every element in this array.
			if(typeof a == "string"){ a = a.split(""); }
			o = o || win.global; f = df.lambda(f);
			var n = a.length, t = new Array(n), i = n - 1, j = 0;
			for(; i >= 0; t[j++] = f.call(o, a[i], i, a), --i);
			return t;	// Array
		},
		everyRev: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary: tests whether all elements in the array pass the test
			//	implemented by the provided function.
			if(typeof a == "string"){ a = a.split(""); }
			o = o || win.global; f = df.lambda(f);
			for(var i = a.length - 1; i >= 0; --i){
				if(!f.call(o, a[i], i, a)){
					return false;	// Boolean
				}
			}
			return true;	// Boolean
		},
		someRev: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary: tests whether some element in the array passes the test
			//	implemented by the provided function.
			if(typeof a == "string"){ a = a.split(""); }
			o = o || win.global; f = df.lambda(f);
			for(var i = a.length - 1; i >= 0; --i){
				if(f.call(o, a[i], i, a)){
					return true;	// Boolean
				}
			}
			return false;	// Boolean
		}
	});
	
	return df;
});