Javascript array best practice to use [] instead of new array?

Question

I read at many tutorials that the current best practices to create a new javascript array is to use

var arr = [] 

instead of

Answer 1

Usually an array literal(var a=[1,2,3] or a=[]) is the way to go.

But once in a while you need an array where the length itself is the defining feature of the array.

var A=Array(n) would (using a literal) need two expressions-

var A=[]; A.length=n;

In any event, you do not need the 'new' operator with the Array constructor, not in the way that you DO need 'new' with a new Date object, say.