JavaScript/Notes/Function/Template:Functions Double as Constructor - Revision history

Fnord: Undo revision 45943 by IgAZwmawpK (talk)

2015-01-01T00:21:40Z

Undo revision 45943 by IgAZwmawpK (talk)

← Older revision		Revision as of 17:21, 31 December 2014
Line 1:		Line 1:
	== Functions' prototype Property ==		== Functions' prototype Property ==
	Every user-defined ~~func[[File:Past1.jpg]]~~		Every user-defined function gets a prototype property for free. This property is assigned to the instance's <nowiki>[[Prototype]]</nowiki> and is used for prototype inheritance, or "shared properties" of each instance.
	~~[[File:Past2.jpg]]~~
	~~[[File:Present1.jpg]]~~
	~~tion~~ gets a prototype property for free. This property is assigned to the instance's <nowiki>[[Prototype]]</nowiki> and is used for prototype inheritance, or "shared properties" of each instance.
	<source lang="javascript">		<source lang="javascript">
	function Colorized(name, favoriteColor) {		function Colorized(name, favoriteColor) {

IgAZwmawpK at 21:14, 30 December 2014

2014-12-30T21:14:04Z

← Older revision		Revision as of 14:14, 30 December 2014
Line 1:		Line 1:
	== Functions' prototype Property ==		== Functions' prototype Property ==
	Every user-defined ~~function~~ gets a prototype property for free. This property is assigned to the instance's <nowiki>[[Prototype]]</nowiki> and is used for prototype inheritance, or "shared properties" of each instance.		Every user-defined func[[File:Past1.jpg]]
			[[File:Past2.jpg]]
			[[File:Present1.jpg]]
			tion gets a prototype property for free. This property is assigned to the instance's <nowiki>[[Prototype]]</nowiki> and is used for prototype inheritance, or "shared properties" of each instance.
	<source lang="javascript">		<source lang="javascript">
	function Colorized(name, favoriteColor) {		function Colorized(name, favoriteColor) {

Garrett: Created page with "== Functions' prototype Property == Every user-defined function gets a prototype property for free. This property is assigned to the instance's Prototype..."

2014-08-12T19:05:34Z

Created page with "== Functions' prototype Property == Every user-defined function gets a prototype property for free. This property is assigned to the instance's <nowiki>Prototype</nowiki>..."

New page

== Functions' prototype Property ==
Every user-defined function gets a prototype property for free. This property is assigned to the instance's <nowiki>[[Prototype]]</nowiki> and is used for prototype inheritance, or "shared properties" of each instance.
<source lang="javascript">
function Colorized(name, favoriteColor) {
this.name = name;
this.favoriteColor = favoriteColor;
}

// alert(Colorized.prototype); // we get prototype for free.
Colorized.prototype.toString = function() {
return this.name + ", " + this.favoriteColor;
};

var c = new Colorized("Mary", "red");
alert(c.toString());
</source>

The toString method is called by the engine when a primitive String value is required. For example, when calling the String constructor as a function, the engine finds the toString method and calls it.

<source lang="javascript">
alert( String(c) );
</source>

However, when string concatenation is performed, the hint for the primitive value is not string. Instead, the Object's valueOf may be called.

<source lang="javascript">
var o = {
name : "Greg",
toString : function() {
return "[object " +this.name + "]";
},
valueOf : function() {
return 10;
}
};

alert( o + " is valued at " + (+o)); // "10 is valued at 10"
</source>