How to extend an existing JavaScript array with another array, without creating a new array

Question

There doesn\'t seem to be a way to extend an existing JavaScript array with another array, i.e. to emulate Python\'s extend method.

I want to achieve th

Answer 1

Super simple, does not count on spread operators or apply, if that's an issue.

b.map(x => a.push(x));

After running some performance tests on this, it's terribly slow, but answers the question in regards to not creating a new array. Concat is significantly faster, even jQuery's $.merge() whoops it.

https://jsperf.com/merge-arrays19b/1