Use the || operator notice

Question

Javascript code:

var a = (b) ? b : 40;

It is working, just NetBeans says: "Use the || operator (Column [where the ? is])". I didn't find any explanation.

What is it?

Thanks!

See http://stackoverflow.com/questions/2802055/what-does-this-construct-x-x-y-mean — Felix Kling, May 22 '12 at 15:14

score 6 · Accepted Answer · answered May 22 '12 at 15:13

If you are just testing for the truthyness of b then you can do this:

var a = b || 40;

… which is shorter and (arguably) more obvious. In JavaScript, || is a short circuit operator. It returns the left hand side if it is true, otherwise it returns the right hand side. (i.e. it doesn't return a boolean unless the input was a boolean).

If you want to see if b is actually defined, then you are better off with:

var a = (typeof b !== "undefined") ? b : 40;

@GáborVarga — I have absolutely no idea what you are asking. — Quentin, May 23 '12 at 09:55

score 3 · Answer 2 · answered May 22 '12 at 15:14

3

The pipes are the or statement. var a = b || 40 says if b is non-falsey value, let a=b, otherwise 40.

answered May 22 '12 at 15:14

Snuffleupagus

5,897
3
28
36

Use the || operator notice

2 Answers2