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Excerpt

Returns the name of the constructor used to create an object...

 

Syntax

typeOf() can be used as a global function, or as a method of any object instance...

Code Block
themeRDark
languagejavascript
linenumberstrue
var returnValue = typeOf(obj);
// or...
var returnValue = obj.typeOf();

Parameters

ParameterTypeMandatoryDescriptionAPI Version
objVariant(error)

By default, typeOf() will return the type of 'this' – the object that it is a method of.

If you pass in an object of any kind as a parameter, typeOf() will return the name of that object's constructor.

1.0

Return value

Returns the string name of the constructor of the class from which the object was instantiated.

Examples

Care must be taken when checking the type of primitive values...

Code Block
themeRDark
languagejavascript
linenumberstrue
// don't do this:
var returnValue = 5.typeOf(); // Syntax Error

// instead, do this:
var returnValue = typeOf(5); // "number"
var returnValue = (5).typeOf(); // "number"
 
// Or if you want a l33t way of doing it:
var returnValue = 5..typeOf(); // "number" (:

If you create a class and instantiate objects from it, typeOf() will return the name of your class, not "object"...

Code Block
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languagejavascript
linenumberstrue
function FooClass() {};
FooClass.typeof(); // "function"
typeof FooClass; // "function"
 
var foo = new FooClass;
foo.typeOf(); // "fooclass", because name of foo constructor is FooClass
typeof foo; // "object" because foo is an object
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Availability
Status
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titleStable

Requires:

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Contents

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Table of Contents
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Type Checking

Topics:

Child pages (Children Display)
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pageType Checking
excerpttrue

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See also

Related articles:

The following examples show the key differences between Javascript's typeof operator and the typeOf() function...

Section
Column
width47%
Code Block
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languagejavascript
titleJavascript's typeof operator
linenumberstrue
typeof {a: 4}; //"object"
typeof [1, 2, 3]; //"object"
typeof function(){}; // "function"
(function() {
  return typeof arguments; //"object"
})();
typeof new ReferenceError; //"object"
typeof new Date; //"object"
typeof /a-z/; //"object"
typeof Math; //"object"
typeof JSON; //"object"
typeof NaN; //"number"
typeof 4; //"number"
typeof new Number(4); //"object"
typeof "abc"; //"string"
typeof new String("abc"); //"object"
typeof true; //"boolean"
typeof new Boolean(true); //"object"
typeof global //"object"
Column
width53%
Code Block
themeRDark
languagejavascript
titletypeOf(stuff)
linenumberstrue
typeOf({a: 4}); //"object"
typeOf([1, 2, 3]); //"array"
typeOf(function(){}); // "function"
(function() {
  return typeOf(arguments); //"arguments"
})();
typeOf(new ReferenceError); //"error"
typeOf(new Date); //"date"
typeOf(/a-z/); //"regexp"
typeOf(Math); //"math"
typeOf(JSON); //"json"
typeOf(NaN)' //"nan"
typeOf(4); //"number"
typeOf(new Number(4)); //"number"
typeOf("abc"); //"string"
typeOf(new String("abc")); //"string"
typeOf(true); //"boolean"
typeOf(new Boolean(true)); //"boolean"
typeOf(global); //"global"