JavaScript Object notation type confusion

Asked Jul 21 '16 at 12:05

Active Jul 21 '16 at 12:12

Viewed 42 times

I am somehow confused about JS object notations. What I know is: There are 2 types of object notations.

var myObj = new Object(); // Object constructor notation
var myObj = {...} // Object literal notation

Object literal is the latest standard and most people use it now a days.

But I have found some people using following notation.

var vm = this;
vm.value = ...;

Can someone explain me about the third type and can tell me, is it literal or constructor.

Thanks.

edited Jul 21 '16 at 12:12

asked Jul 21 '16 at 12:05

h_h

`console.log(this)` – epascarello Jul 21 '16 at 12:07
1

The first two are syntax used to create a new object. The last is just working with an existing object. – Jul 21 '16 at 12:08
Hi, If there is no object created before this, then its using default object??? – h_h Jul 21 '16 at 12:10
1

The last one depends on the context, i.e. where that piece of code is placed. – JJJ Jul 21 '16 at 12:14
1

If it isn't in a function this refers to the window object. When you call vm = this you copy all the properties of the window object to vm. – David Jul 21 '16 at 12:14
hmm, thanks @David Now I am getting clear picture – h_h Jul 21 '16 at 12:15
2

@David `vm` will then point to the window object. There is no copying involved. – JJJ Jul 21 '16 at 12:16
Oh right so if I overwrite vm.innerWidth to something else I will be changing that value for the window object too. – David Jul 21 '16 at 12:20

0 Answers0