CODEWITHSUNDEEP
javascript
Thomson
Thomson

Reputation: 21714

How to call a function through a variable?

I have the below code, 

function MyFunc(){}
var myFunc = new MyFunc();
myFunc();  // through TypeError this line,

How can I make it to work if I want to call the function through the variable?

Upvotes: 0

Views: 264

Answers (8)

T.J. Crowder
T.J. Crowder

Reputation: 1075785

In JavaScript, functions are first-class objects. To refer to the object, just use the function name. So if you just want to call MyFunc through the myFunc variable, just assign MyFunc to myFunc:

function MyFunc(){}
var myFunc = MyFunc; // <=== Change on this line
myFunc();

Your original line:

var myFunc = new MyFunc();

...calls MyFunc as a constructor function, and myFunc (the variable) will receive a reference to whatever object is created as a result. (Just like, say, var now = new Date(); creates a Date object and assigns it to now.)

Upvotes: 2

DhruvPathak
DhruvPathak

Reputation: 43265

http://jsfiddle.net/dWpEz/

var myFunc = function (){ alert("YES"); }
myFunc();

Upvotes: 1

OverZealous
OverZealous

Reputation: 39580

I think what you wanted is this:

var myFunc = function(){
    ....
};

myFunc();

This creates a variable named myFunc which is a reference to the anonymous function.

Upvotes: 1

Stephen
Stephen

Reputation: 3432

So calling new MyFunc() will excute whatever code you put in there - it acts somewhat like a constructor in other languages - although not exactly.

If it wasn't a typo and you wanted to define a function on your class called myFunc if you wanted by doing something like

MyFunc.prototype.myFunc = function() {
}

Upvotes: 1

Pratik
Pratik

Reputation: 30855

you create the object of the function the new keyword was used to create the object

var myfun_var = function MyFunc(){
       alert("hello");
}

and call myfun_var();

Upvotes: 1

Jeremy Banks
Jeremy Banks

Reputation: 129746

By doing new MyFunc(), you're treating MyFunc as a constructor and are creating an object with it. This is treating MyFunc as a class that you want an instance of. You just want to assign another variable to point to the function, so you don't want the new or the ().

You want to just set var myFunc = MyFunc, and then calling myFunc() will work.

Upvotes: 6

Decko
Decko

Reputation: 19375

In javascript, a function is just another variable.

function MyFunc(){}

is the same as

var MyFunc = function(){};

Thus this is also valid

function MyFunc(){}
var myfunc = MyFunc;
myfunc();

Upvotes: 1

Evan Trimboli
Evan Trimboli

Reputation: 30092

The case doesn't match. Javascript is case sensitive.

Upvotes: -2

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