If else shorthand inside array .push()

Question

Why I can do if else shorthand inside .push() function ? like

var arr = [];
arr.push(test||null);
// nothing

But

var arr = [];
var test = test||null;
arr.push(test);
// [null]

I need to insert null if variable is undefined.

Why I cant use test||null inside .push() function ?

Your first example causes an error, that's why nothing happens. Please take a look at the console. — Teemu, Oct 15 '13 at 08:04

score 3 · Answer 1 · answered Oct 15 '13 at 08:06

3

arr.push(typeof(test) == "undefined" ? null: test);

answered Oct 15 '13 at 08:06

lastr2d2

Thanks , Ahhhh I looking longer version, But work :P – l2aelba Oct 15 '13 at 08:07
1

You're code will work if you define test, like @MC ND says in his answer. – Adrian Lynch Jul 07 '16 at 07:47
this is a late reply but `typeof` works even the variable is not declared. – lastr2d2 Feb 25 '21 at 07:49

score 2 · Accepted Answer · answered Oct 15 '13 at 08:46

Yes. You can use

arr.push(test||null);

if you define test. Why your second code is working ?

var arr = [];
var test = test||null;
arr.push(test);
// [null]

It's working because you have defined test.

So, this works

var test;
var arr = [];
arr.push(test||null);

2 Answers2