lang.js

define(["./kernel", "../has", "./sniff"], function(dojo, has, sniff){
	// module:
	//		dojo/_base/lang
	// summary:
	//		This module defines the dojo core Javascript language extensions.


	has.add("bug-for-in-skips-shadowed", function(){
		// if true, the for-in interator skips object properties that exist in Object's prototype (IE 6 - ?)
		for(var i in {toString: 1}){
			return 0;
		}
		return 1;
	});

	var empty = {},

		_extraNames = has("bug-for-in-skips-shadowed") ? "hasOwnProperty.valueOf.isPrototypeOf.propertyIsEnumerable.toLocaleString.toString.constructor".split(".") : [],

		_extraLen = _extraNames.length,

		_mixin = function(/*Object*/ target, /*Object*/ source){
			// summary:
			//		Adds all properties and methods of source to target. This addition
			//		is "prototype extension safe", so that instances of objects
			//		will not pass along prototype defaults.
			var name, s, i;
			for(name in source){
				// the "tobj" condition avoid copying properties in "source"
				// inherited from Object.prototype.	 For example, if target has a custom
				// toString() method, don't overwrite it with the toString() method
				// that source inherited from Object.prototype
				s = source[name];
				if(!(name in target) || (target[name] !== s && (!(name in empty) || empty[name] !== s))){
					target[name] = s;
				}
			}

			if(has("bug-for-in-skips-shadowed")){
				if(source){
					for(i = 0; i < _extraLen; ++i){
						name = _extraNames[i];
						s = source[name];
						if(!(name in target) || (target[name] !== s && (!(name in empty) || empty[name] !== s))){
							target[name] = s;
						}
					}
				}
			}

			return target; // Object
		},

		mixin = function(/*Object*/obj, /*Object...*/props){
			// summary:
			//		Adds all properties and methods of props to obj and returns the
			//		(now modified) obj.
			//	description:
			//		`lang.mixin` can mix multiple source objects into a
			//		destination object which is then returned. Unlike regular
			//		`for...in` iteration, `lang.mixin` is also smart about avoiding
			//		extensions which other toolkits may unwisely add to the root
			//		object prototype
			//	obj:
			//		The object to mix properties into. Also the return value.
			//	props:
			//		One or more objects whose values are successively copied into
			//		obj. If more than one of these objects contain the same value,
			//		the one specified last in the function call will "win".
			//	example:
			//		make a shallow copy of an object
			//	| var copy = lang.mixin({}, source);
			//	example:
			//		many class constructors often take an object which specifies
			//		values to be configured on the object. In this case, it is
			//		often simplest to call `lang.mixin` on the `this` object:
			//	| dojo.declare("acme.Base", null, {
			//	|		constructor: function(properties){
			//	|			// property configuration:
			//	|			lang.mixin(this, properties);
			//	|
			//	|			console.log(this.quip);
			//	|			//	...
			//	|		},
			//	|		quip: "I wasn't born yesterday, you know - I've seen movies.",
			//	|		// ...
			//	| });
			//	|
			//	| // create an instance of the class and configure it
			//	| var b = new acme.Base({quip: "That's what it does!" });
			//	example:
			//		copy in properties from multiple objects
			//	| var flattened = lang.mixin(
			//	|		{
			//	|			name: "Frylock",
			//	|			braces: true
			//	|		},
			//	|		{
			//	|			name: "Carl Brutanananadilewski"
			//	|		}
			//	| );
			//	|
			//	| // will print "Carl Brutanananadilewski"
			//	| console.log(flattened.name);
			//	| // will print "true"
			//	| console.log(flattened.braces);
			if(!obj){ obj = {}; }
			for(var i = 1, l = arguments.length; i < l; i++){
				_mixin(obj, arguments[i]);
			}
			return obj; // Object
		},

		getProp = function(/*Array*/parts, /*Boolean*/create, /*Object*/context){
			var p, i = 0, dojoGlobal = dojo.global;
			if(!context){
				if(!parts.length){
					return dojoGlobal;
				}else{
					p = parts[i++];
					try{
						context = dojo.scopeMap[p] && dojo.scopeMap[p][1];
					}catch(e){}
					context = context || (p in dojoGlobal ? dojoGlobal[p] : (create ? dojoGlobal[p] = {} : undefined));
				}
			}
			while(context && (p = parts[i++])){
				context = (p in context ? context[p] : (create ? context[p] = {} : undefined));
			}
			return context; // mixed
		},

		setObject = function(/*String*/name, /*Object*/value, /*Object?*/context){
			// summary:
			//		Set a property from a dot-separated string, such as "A.B.C"
			//	description:
			//		Useful for longer api chains where you have to test each object in
			//		the chain, or when you have an object reference in string format.
			//		Objects are created as needed along `path`. Returns the passed
			//		value if setting is successful or `undefined` if not.
			//	name:
			//		Path to a property, in the form "A.B.C".
			//	context:
			//		Optional. Object to use as root of path. Defaults to
			//		`dojo.global`.
			//	example:
			//		set the value of `foo.bar.baz`, regardless of whether
			//		intermediate objects already exist:
			//	| lang.setObject("foo.bar.baz", value);
			//	example:
			//		without `lang.setObject`, we often see code like this:
			//	| // ensure that intermediate objects are available
			//	| if(!obj["parent"]){ obj.parent = {}; }
			//	| if(!obj.parent["child"]){ obj.parent.child = {}; }
			//	| // now we can safely set the property
			//	| obj.parent.child.prop = "some value";
			//		whereas with `lang.setObject`, we can shorten that to:
			//	| lang.setObject("parent.child.prop", "some value", obj);
			var parts = name.split("."), p = parts.pop(), obj = getProp(parts, true, context);
			return obj && p ? (obj[p] = value) : undefined; // Object
		},

		getObject = function(/*String*/name, /*Boolean?*/create, /*Object?*/context){
			// summary:
			//		Get a property from a dot-separated string, such as "A.B.C"
			//	description:
			//		Useful for longer api chains where you have to test each object in
			//		the chain, or when you have an object reference in string format.
			//	name:
			//		Path to an property, in the form "A.B.C".
			//	create:
			//		Optional. Defaults to `false`. If `true`, Objects will be
			//		created at any point along the 'path' that is undefined.
			//	context:
			//		Optional. Object to use as root of path. Defaults to
			//		'dojo.global'. Null may be passed.
			return getProp(name.split("."), create, context); // Object
		},

		exists = function(/*String*/name, /*Object?*/obj){
			//	summary:
			//		determine if an object supports a given method
			//	description:
			//		useful for longer api chains where you have to test each object in
			//		the chain. Useful for object and method detection.
			//	name:
			//		Path to an object, in the form "A.B.C".
			//	obj:
			//		Object to use as root of path. Defaults to
			//		'dojo.global'. Null may be passed.
			//	example:
			//	| // define an object
			//	| var foo = {
			//	|		bar: { }
			//	| };
			//	|
			//	| // search the global scope
			//	| lang.exists("foo.bar"); // true
			//	| lang.exists("foo.bar.baz"); // false
			//	|
			//	| // search from a particular scope
			//	| lang.exists("bar", foo); // true
			//	| lang.exists("bar.baz", foo); // false
			return getObject(name, false, obj) !== undefined; // Boolean
		},

		opts = Object.prototype.toString,

		// Crockford (ish) functions

		isString = function(/*anything*/ it){
			//	summary:
			//		Return true if it is a String
			return (typeof it == "string" || it instanceof String); // Boolean
		},

		isArray = function(/*anything*/ it){
			//	summary:
			//		Return true if it is an Array.
			//		Does not work on Arrays created in other windows.
			return it && (it instanceof Array || typeof it == "array"); // Boolean
		},

		isFunction = function(/*anything*/ it){
			// summary:
			//		Return true if it is a Function
			return opts.call(it) === "[object Function]";
		},

		isObject = function(/*anything*/ it){
			// summary:
			//		Returns true if it is a JavaScript object (or an Array, a Function
			//		or null)
			return it !== undefined &&
				(it === null || typeof it == "object" || isArray(it) || isFunction(it)); // Boolean
		},

		isArrayLike = function(/*anything*/ it){
			//	summary:
			//		similar to dojo.isArray() but more permissive
			//	description:
			//		Doesn't strongly test for "arrayness".  Instead, settles for "isn't
			//		a string or number and has a length property". Arguments objects
			//		and DOM collections will return true when passed to
			//		dojo.isArrayLike(), but will return false when passed to
			//		dojo.isArray().
			//	returns:
			//		If it walks like a duck and quacks like a duck, return `true`
			return it && it !== undefined && // Boolean
				// keep out built-in constructors (Number, String, ...) which have length
				// properties
				!isString(it) && !isFunction(it) &&
				!(it.tagName && it.tagName.toLowerCase() == 'form') &&
				(isArray(it) || isFinite(it.length));
		},

		isAlien = function(/*anything*/ it){
			// summary:
			//		Returns true if it is a built-in function or some other kind of
			//		oddball that *should* report as a function but doesn't
			return it && !isFunction(it) && /\{\s*\[native code\]\s*\}/.test(String(it)); // Boolean
		},

		extend = function(/*Object*/ constructor, /*Object...*/ props){
			// summary:
			//		Adds all properties and methods of props to constructor's
			//		prototype, making them available to all instances created with
			//		constructor.
			for(var i=1, l=arguments.length; i<l; i++){
				_mixin(constructor.prototype, arguments[i]);
			}
			return constructor; // Object
		},

		_hitchArgs = function(scope, method /*,...*/){
			var pre = _toArray(arguments, 2);
			var named = isString(method);
			return function(){
				// arrayify arguments
				var args = _toArray(arguments);
				// locate our method
				var f = named ? (scope||dojo.global)[method] : method;
				// invoke with collected args
				return f && f.apply(scope || this, pre.concat(args)); // mixed
			}; // Function
		},

		hitch = function(/*Object*/scope, /*Function|String*/method /*,...*/){
			//	summary:
			//		Returns a function that will only ever execute in the a given scope.
			//		This allows for easy use of object member functions
			//		in callbacks and other places in which the "this" keyword may
			//		otherwise not reference the expected scope.
			//		Any number of default positional arguments may be passed as parameters
			//		beyond "method".
			//		Each of these values will be used to "placehold" (similar to curry)
			//		for the hitched function.
			//	scope:
			//		The scope to use when method executes. If method is a string,
			//		scope is also the object containing method.
			//	method:
			//		A function to be hitched to scope, or the name of the method in
			//		scope to be hitched.
			//	example:
			//	|	dojo.hitch(foo, "bar")();
			//		runs foo.bar() in the scope of foo
			//	example:
			//	|	dojo.hitch(foo, myFunction);
			//		returns a function that runs myFunction in the scope of foo
			//	example:
			//		Expansion on the default positional arguments passed along from
			//		hitch. Passed args are mixed first, additional args after.
			//	|	var foo = { bar: function(a, b, c){ console.log(a, b, c); } };
			//	|	var fn = dojo.hitch(foo, "bar", 1, 2);
			//	|	fn(3); // logs "1, 2, 3"
			//	example:
			//	|	var foo = { bar: 2 };
			//	|	dojo.hitch(foo, function(){ this.bar = 10; })();
			//		execute an anonymous function in scope of foo

			if(arguments.length > 2){
				return _hitchArgs.apply(dojo, arguments); // Function
			}
			if(!method){
				method = scope;
				scope = null;
			}
			if(isString(method)){
				scope = scope || dojo.global;
				if(!scope[method]){ throw(['dojo.hitch: scope["', method, '"] is null (scope="', scope, '")'].join('')); }
				return function(){ return scope[method].apply(scope, arguments || []); }; // Function
			}
			return !scope ? method : function(){ return method.apply(scope, arguments || []); }; // Function
		},

		/*=====
		dojo.delegate = function(obj, props){
			//	summary:
			//		Returns a new object which "looks" to obj for properties which it
			//		does not have a value for. Optionally takes a bag of properties to
			//		seed the returned object with initially.
			//	description:
			//		This is a small implementaton of the Boodman/Crockford delegation
			//		pattern in JavaScript. An intermediate object constructor mediates
			//		the prototype chain for the returned object, using it to delegate
			//		down to obj for property lookup when object-local lookup fails.
			//		This can be thought of similarly to ES4's "wrap", save that it does
			//		not act on types but rather on pure objects.
			//	obj:
			//		The object to delegate to for properties not found directly on the
			//		return object or in props.
			//	props:
			//		an object containing properties to assign to the returned object
			//	returns:
			//		an Object of anonymous type
			//	example:
			//	|	var foo = { bar: "baz" };
			//	|	var thinger = dojo.delegate(foo, { thud: "xyzzy"});
			//	|	thinger.bar == "baz"; // delegated to foo
			//	|	foo.thud == undefined; // by definition
			//	|	thinger.thud == "xyzzy"; // mixed in from props
			//	|	foo.bar = "thonk";
			//	|	thinger.bar == "thonk"; // still delegated to foo's bar
		}
		=====*/

		delegate = (function(){
			// boodman/crockford delegation w/ cornford optimization
			function TMP(){}
			return function(obj, props){
				TMP.prototype = obj;
				var tmp = new TMP();
				TMP.prototype = null;
				if(props){
					_mixin(tmp, props);
				}
				return tmp; // Object
			};
		})(),

		/*=====
		dojo._toArray = function(obj, offset, startWith){
			//	summary:
			//		Converts an array-like object (i.e. arguments, DOMCollection) to an
			//		array. Returns a new Array with the elements of obj.
			//	obj: Object
			//		the object to "arrayify". We expect the object to have, at a
			//		minimum, a length property which corresponds to integer-indexed
			//		properties.
			//	offset: Number?
			//		the location in obj to start iterating from. Defaults to 0.
			//		Optional.
			//	startWith: Array?
			//		An array to pack with the properties of obj. If provided,
			//		properties in obj are appended at the end of startWith and
			//		startWith is the returned array.
		}
		=====*/

		efficient = function(obj, offset, startWith){
			return (startWith||[]).concat(Array.prototype.slice.call(obj, offset||0));
		},

		_toArray =
			has("ie") ?
				(function(){
					function slow(obj, offset, startWith){
						var arr = startWith||[];
						for(var x = offset || 0; x < obj.length; x++){
							arr.push(obj[x]);
						}
						return arr;
					}
					return function(obj){
						return ((obj.item) ? slow : efficient).apply(this, arguments);
					};
				})() : efficient,

		partial = function(/*Function|String*/method /*, ...*/){
			//	summary:
			//		similar to hitch() except that the scope object is left to be
			//		whatever the execution context eventually becomes.
			//	description:
			//		Calling dojo.partial is the functional equivalent of calling:
			//		|	dojo.hitch(null, funcName, ...);
			var arr = [ null ];
			return hitch.apply(dojo, arr.concat(_toArray(arguments))); // Function
		},

		clone = function(/*anything*/ o){
			// summary:
			//		Clones objects (including DOM nodes) and all children.
			//		Warning: do not clone cyclic structures.
			if(!o || typeof o != "object" || isFunction(o)){
				// null, undefined, any non-object, or function
				return o;	// anything
			}
			if(o.nodeType && "cloneNode" in o){
				// DOM Node
				return o.cloneNode(true); // Node
			}
			if(o instanceof Date){
				// Date
				return new Date(o.getTime());	// Date
			}
			if(o instanceof RegExp){
				// RegExp
				return new RegExp(o);   // RegExp
			}
			var r, i, l, s, name;
			if(isArray(o)){
				// array
				r = [];
				for(i = 0, l = o.length; i < l; ++i){
					if(i in o){
						r.push(clone(o[i]));
					}
				}
	// we don't clone functions for performance reasons
	//		}else if(d.isFunction(o)){
	//			// function
	//			r = function(){ return o.apply(this, arguments); };
			}else{
				// generic objects
				r = o.constructor ? new o.constructor() : {};
			}
			for(name in o){
				// the "tobj" condition avoid copying properties in "source"
				// inherited from Object.prototype.  For example, if target has a custom
				// toString() method, don't overwrite it with the toString() method
				// that source inherited from Object.prototype
				s = o[name];
				if(!(name in r) || (r[name] !== s && (!(name in empty) || empty[name] !== s))){
					r[name] = clone(s);
				}
			}
			if(has("bug-for-in-skips-shadowed")){
				var extraNames = _extraNames;
				for(i = extraNames.length; i;){
					name = extraNames[--i];
					s = o[name];
					if(!(name in r) || (r[name] !== s && (!(name in empty) || empty[name] !== s))){
						r[name] = s; // functions only, we don't clone them
					}
				}
			}
			return r; // Object
		},

		/*=====
		dojo.trim = function(str){
			//	summary:
			//		Trims whitespace from both sides of the string
			//	str: String
			//		String to be trimmed
			//	returns: String
			//		Returns the trimmed string
			//	description:
			//		This version of trim() was selected for inclusion into the base due
			//		to its compact size and relatively good performance
			//		(see [Steven Levithan's blog](http://blog.stevenlevithan.com/archives/faster-trim-javascript)
			//		Uses String.prototype.trim instead, if available.
			//		The fastest but longest version of this function is located at
			//		dojo.string.trim()
			return "";	// String
		}
		=====*/

		trim = String.prototype.trim ?
			function(str){ return str.trim(); } :
			function(str){ return str.replace(/^\s\s*/, '').replace(/\s\s*$/, ''); },

		/*=====
		dojo.replace = function(tmpl, map, pattern){
			//	summary:
			//		Performs parameterized substitutions on a string. Throws an
			//		exception if any parameter is unmatched.
			//	tmpl: String
			//		String to be used as a template.
			//	map: Object|Function
			//		If an object, it is used as a dictionary to look up substitutions.
			//		If a function, it is called for every substitution with following
			//		parameters: a whole match, a name, an offset, and the whole template
			//		string (see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/String/replace
			//		for more details).
			//	pattern: RegEx?
			//		Optional regular expression objects that overrides the default pattern.
			//		Must be global and match one item. The default is: /\{([^\}]+)\}/g,
			//		which matches patterns like that: "{xxx}", where "xxx" is any sequence
			//		of characters, which doesn't include "}".
			//	returns: String
			//		Returns the substituted string.
			//	example:
			//	|	// uses a dictionary for substitutions:
			//	|	dojo.replace("Hello, {name.first} {name.last} AKA {nick}!",
			//	|		{
			//	|			nick: "Bob",
			//	|			name: {
			//	|				first:	"Robert",
			//	|				middle: "X",
			//	|				last:		"Cringely"
			//	|			}
			//	|		});
			//	|	// returns: Hello, Robert Cringely AKA Bob!
			//	example:
			//	|	// uses an array for substitutions:
			//	|	dojo.replace("Hello, {0} {2}!",
			//	|		["Robert", "X", "Cringely"]);
			//	|	// returns: Hello, Robert Cringely!
			//	example:
			//	|	// uses a function for substitutions:
			//	|	function sum(a){
			//	|		var t = 0;
			//	|		dojo.forEach(a, function(x){ t += x; });
			//	|		return t;
			//	|	}
			//	|	dojo.replace(
			//	|		"{count} payments averaging {avg} USD per payment.",
			//	|		dojo.hitch(
			//	|			{ payments: [11, 16, 12] },
			//	|			function(_, key){
			//	|				switch(key){
			//	|					case "count": return this.payments.length;
			//	|					case "min":		return Math.min.apply(Math, this.payments);
			//	|					case "max":		return Math.max.apply(Math, this.payments);
			//	|					case "sum":		return sum(this.payments);
			//	|					case "avg":		return sum(this.payments) / this.payments.length;
			//	|				}
			//	|			}
			//	|		)
			//	|	);
			//	|	// prints: 3 payments averaging 13 USD per payment.
			//	example:
			//	|	// uses an alternative PHP-like pattern for substitutions:
			//	|	dojo.replace("Hello, ${0} ${2}!",
			//	|		["Robert", "X", "Cringely"], /\$\{([^\}]+)\}/g);
			//	|	// returns: Hello, Robert Cringely!
			return "";	// String
		}
		=====*/

		_pattern = /\{([^\}]+)\}/g,

		replace = function(tmpl, map, pattern){
			return tmpl.replace(pattern || _pattern, isFunction(map) ?
				map : function(_, k){ return getObject(k, false, map); });
		},

		lang = {
			_extraNames:_extraNames,
			_mixin:_mixin,
			mixin:mixin,
			setObject:setObject,
			getObject:getObject,
			exists:exists,
			isString: isString,
			isArray: isArray,
			isFunction: isFunction,
			isObject: isObject,
			isArrayLike: isArrayLike,
			isAlien: isAlien,
			extend: extend,
			_hitchArgs: _hitchArgs,
			hitch: hitch,
			delegate: delegate,
			_toArray: _toArray,
			partial: partial,
			clone: clone,
			trim: trim,
			replace: replace
		};

	has("dojo-1x-base") && mixin(dojo, lang);
	return lang;
});