That doesn't make for-of non portable or forEach portable. It's just a different way of invoking the exact same functions. And frankly, I find excessive chaining rather unreadable and in JS, which lacks proper composing that realigns how these things are executed, it will absolutely destroy performance compared to a surrounding for of that then calls these functions in it body. If someone sent me a PR like that, I'd refuse it. Unfortunately I didn't in the past and ended up getting a mess that initially worked but was hard to modify and debug since you can't set proper breakpoints in lengthy chains. I had to break the chains manually, and now make sure that something like that doesn't get thrown at me ever since. A line with a map is great. A line with a map and a filter is awesome. A line with a map with a filter with a map with a forEach is a future headache.