Hacker News Reader

Comment by rfw | Hacker News Reader

Neat! Extension methods and getting rid of "var that = this;" in one!

It seems that it also extends to full expressions on the right-hand side of ::, so you can even do, for using Array operations over things that look like arrays but not quite:

    document.querySelectorAll('p')::([].map)(f)

instead of:

    [].map.call(document.querySelectorAll('p'), f)

(replace [].map with Array.prototype.map if it feels less gross)

View on HN

This also works, by the way:

    [...document.querySelectorAll('p')].map(f)

In the future, NodeList could extend Array which would make these workarounds redundant. Extending Array was made possible by ES6.

Anyhow, I think having some kind of extension methods would be great.

> In the future, NodeList could extend Array which would make these workarounds redundant.

It would break the web, unfortunately. (We've experimented with NodeList.prototype.__proto__ being Array.prototype instead of Object.prototype and it breaks sites, and ES6's extends notion implies that.)

Why do that in the callback way at all? Why not simple

    for(const el of document.querySelectorAll('p')) {}

Why have the overhead of a callback to begin with. It reads SO much better as well.

It has different semantics. Your code is equivalent to a `forEach` call, not `map`. Calling `map` returns a new array containing the results of the callback, while a for loop or a `forEach` don't.

I find ".bind(this)" to be preferable over "var that = this" anyway.

Wow, what an improvement! In fact, why don't we just drop keywords altogether and adopt APL-like syntax for better code concision? Here, let me offer an example of how superior APL is:

  (~R∊R∘.×R)/R←1↓ιR

Reply on news.ycombinator.com