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: https://www.phpied.com/3-ways-to-define-a-javascript-class/ — dgiugg, Mar 30 '17 at 16:24
Possible duplicate of [How do you create a method for a custom object in JavaScript?](http://stackoverflow.com/questions/504803/how-do-you-create-a-method-for-a-custom-object-in-javascript) — Heretic Monkey, Mar 30 '17 at 16:28

score 1 · Answer 1 · answered Mar 30 '17 at 16:23

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();

score 0 · Answer 2 · answered Mar 30 '17 at 16:24

 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.

score 0 · Answer 3 · answered Mar 30 '17 at 16:30

0

Another way using the Class declaration:

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


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

answered Mar 30 '17 at 16:30

funcoding

3 Answers3