Call JavaScript function in another file using JavaScript object

Question

I want to call one JavaScript function from another JavaScript file

below is my code:

 var exJS = function () {
     function coolMethod() {
       alert("hello suraj");
     }
  }

when I call the function

var myClass = new exJS();
myClass.coolMethod();

Why do I get the error that coolmethod is not defined?

Google: "define class javascript". First result: phpied.com/3-ways-to-define-a-javascript-class — dgiugg
– dgiugg, Commented Mar 30, 2017 at 16:24
Possible duplicate of How do you create a method for a custom object in JavaScript? — Heretic Monkey
– Heretic Monkey, Commented Mar 30, 2017 at 16:28

Rory McCrossan · Accepted Answer · 2017-03-30 16:23:59Z

1

For it to be accessible externally, you need to define the child function using the this reference of the parent function, like this:

var exJS = function() {
  this.coolMethod = function() {
    alert("hello suraj");
  }
}

var myClass = new exJS();
myClass.coolMethod();

answered Mar 30, 2017 at 16:23

Rory McCrossan

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Comments

Ramanlfc · Accepted Answer · 2017-03-30 16:24:30Z

0

 var exJS = function (){
  function coolMethod() {
    alert("hello suraj");
   }
}

this essentially translates to :

 var exJS = function (){
  var coolMethod = function () {
    alert("hello suraj");
   };
}

as you can see coolMethod is just a local variable pointing to a function.

use :

this.coolMethod = function () {
        alert("hello suraj");
       };

so coolMethod becomes a member of exJS.

answered Mar 30, 2017 at 16:24

Ramanlfc

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funcoding · Accepted Answer · 2017-03-30 16:30:31Z

0

Another way using the Class declaration:

class exJS {
    coolMethod () {
    alert("hello suraj");
  }
}


var myClass = new exJS();
myClass.coolMethod();

answered Mar 30, 2017 at 16:30

funcoding

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