JS Array vs [], and whether or not NULL is judged

The two are basically the same, and the only difference is initialization:

varA = [],//These is the sameb =NewArray (),//A and B is arrays with length 0C= [' foo ', ' Bar '],//These is the sameD =NewArray (' foo ', ' Bar '),//C and D is arrays with 2 strings//these is different:e = [3]//E.length = = 1, e[0] = = 3f =NewArray (3),//F.length = = 3, f[0] = = undefined

That is, array (ARG), where Arg refers to the length of the generated array.

Reference: What'sthe difference between "array ()" and "[]" while declaring a JavaScript array?

Check if the array is empty:

if (Array = = = Undefined | | array.length = = 0)    {//  array empty or does not exist}

JS Array vs [], and whether or not NULL is judged