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!

Answer 1

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;