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

Also note that doing:

var x = [5];

Is different than doing:

var x = new Array(5);

The former creates an initializes an array with one element with value of 5. The later creates an initializes an array with 5 undefined elements.