Question

Possible Duplicate:
What does “options = options || {}” mean in Javascript?

Looking at the YouTube source…

var yt = yt || {};

Does that mean.. set yt to yt if yt exists, else create a new object?

If that’s the case, I didn’t think you can put a condition when declaring a variable.

Answer 1

Assign the value of yt back to yt unless it is any of 0, NaN, false, null, "", or undefined (i.e. it’s falsy), in which case assign {} to yt.

This works because each of the values in the list above evaluate to false in a boolean expression.