Comma operator of JavaScript

var a = [0, 1, 2][0, 1, 2];

What is value of a?

var b = 0, 1, 2;

What is value of b?

b is last element of 0, 1, 2 so

b === 2

So a === [0, 1, 2][2];

a === 2;

A grammar utility of JavaScript. 😉