Pretty sure it will not. Nothing is lazy in JS by default:

> One caveat of spreading iterables: JavaScript creates an array out of the elements of the iterable. That might be very wasteful for extremely large collections. For example, if we spread a large collection just to find an element in the collection, it might have been wiser to iterate over the element using its iterator directly.

> And if we have an infinite collection, spreading is going to fail outright.

http://raganwald.com/2015/02/17/lazy-iteratables-in-javascri...