Please read the last bullet point in this paragraph of FAQ.

You have a misplaced ) there, it's:

"test".match(/foo/) || []; // returns []

Well: If you call match with a Regexp on a string and there are no matches, it returns null.

.match(/foo/ || []);

It's not that, it's .match(/foo/) || []. Did you miss a parenthase?

I don't understand it either. People are suggesting that [] is returned in place of null. but:

"test".match(/foo/ || []); // returns null, not []

[] is also a truthy value, not falsy:

if ([]) true // true

if there's no match, you don't get an empty array, but you do get a falsy value.