Difference between defining classes in different ways in JavaScript

Question

What is the difference between defining classed in the following ways?

1)

var parentCls = {
    name:'John',
    callMe : function (){
        alert('Method gets called');
    }
}
parentCls.callMe();

2)

function parentCls(){
    this.name='John';
    this.callMe = function (){
        alert('Method gets called');
    }
}
parentCls.CallMe()

Thanks

Thansk for the link! So now my question is also what is the difference between :1)var functionOne = function() { // Some code }; 2) var functionOne = { // Some code }; — user385729, May 06 '14 at 23:32
It's a bit misleading to talk about "classes" in JavaScript (even though ES6 will finally use the `class` keyword). JavaScript has objects and constructor functions, which create objects. — Felix Kling, May 07 '14 at 00:15

score 3 · Accepted Answer · edited May 23 '17 at 11:44

3

This is an object:

var parentCls = {
    name:'John',
    callMe : function (){
        alert('Method gets called');
    }
}
parentCls.callMe();

This is a function:

function parentCls(){
    this.name='John';
    this.callMe = function (){
        alert('Method gets called');
    }
}
parentCls.callMe()

In this code, you will receive an error. You can't access parentCls.callMe()

edited May 23 '17 at 11:44

Community

answered May 06 '14 at 23:43

Colandus

sorry I forgot to add: var obj = new parentCls(); obj.callMe(); So why this video (https://www.youtube.com/watch?v=PMfcsYzj-9M) at 13:20 says AnswerPrototype is a class? Is it a typo? – user385729 May 06 '14 at 23:48
It's not a typo, a class is practically an object. – Colandus May 06 '14 at 23:51

score 0 · Answer 2 · answered May 06 '14 at 23:41

Usually you use function parentCls() if you have something to pass to it. For example

function parentCls(name){
    this.name=name;
    this.callMe = function (){
        alert('Method gets called');
    }
}

So you can create an object like var newObject = new parentCls('abc');

2 Answers2