What does || mean?

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What does this construct mean?

I'm encountering this syntax for the first time and am not sure what it's doing:

self.name = _searchString(settings.dataBrowser) || "An unknown browser";

What does the or (double pipes) condition do? When would self.name be set to the second value?

I believe that happens when the first is null? I could be wrong though. — slandau, Oct 10 '11 at 20:26

score 6 · Accepted Answer · answered Oct 10 '11 at 20:26

6

This is the logical or operator.

It evaluates to its first "truthy" operand.

In particular, it will evaluate to the second operand if the first operand is "falsy" — null, false, undefined, 0, "", or NaN.

answered Oct 10 '11 at 20:26

SLaks

Basically a coalesce operator! Gotta love it.. – John Strickler Oct 10 '11 at 20:38

score 0 · Answer 2 · answered Oct 10 '11 at 20:27

0

Crockford calls / called it a default operator

answered Oct 10 '11 at 20:27

Allen Rice

score 0 · Answer 3 · edited May 23 '17 at 12:02

0

this is directly related to a question i have asked, you can read about it here Short-circuit evaluation via the AND operator in PHP

so basically, it sets self.name to the value returned from the function, but if the function returns false, it sets itself to "An unknown browser";

edited May 23 '17 at 12:02

Community

answered Oct 10 '11 at 20:27

Jan Dragsbaek

3 Answers3