Question

In Javascript what is this type?

a = {x :1 , y: 2};

In many js tutorials, I’ve not seen this just:
var a = new a();.

Answer 1

a is an “object“.

Outside of Javascript it is usually known as an associative array / dictionary.

To declare a with the new expression (not recommended):

var a = new Object();
a.x = 5;
a.y = 6;