True generally, but irrelevant here: the function in question is RegExp.prototype.match. By definition, it never returns undefined, but only an array or null. The only way `match == undefined` could be true would be if smething had overridden RegExp.prototype.match, which would be… surprising and worthy of explicit note.

Also match[1] will never be undefined: it’ll either throw an exception, or be a string. No, this is just a bug, a poorly written guard that fails to guard what it was supposed to, and I suppose an exception is just silently swallowed and treated equivalently to the intended early return. But the clause should be changed to just `if (!match) return;` or similar.