On: Gov.uk drops jQuery from their front end

[dhritzkiv]

what do you mean by "wasteful"?

[megous → dhritzkiv]

Creating an array, populating it with however many elements just to be able to call some methods and destroying it immediately afterwards. And doing it all over the app, just because it's syntactically convenient. (all while you already have an iterable collection in the form of NodeList)

[hombre_fatal → megous]

It is a bit weird to consume an iterator into an array when a NodeList is already iterable.

Not sure why it caught on.

[shirogane86x → hombre_fatal]

I'm also one of those guys that will always spread NodeLists (and other iterable-but-not-array type of objects) but it's really only because I find functional style a lot more readable than imperative style for loops. It might be iterable, but if it doesn't have map/filter/reduce and friends, might as well not be for me.

[megous → shirogane86x]

NodeList.prototype.filter = Array.prototype.filter;

and you can querySelectorAll('...').filter(el => ...) without any copies.

ditto for other mentioned functions. Prototypal nature of Javascript is there for a reason.

[shirogane86x → megous]

In every single project or company I've ever worked on/with, monkey patching was _extremely_ frowned upon (for good reasons). Also, how would you be able to filter without any copies? you'd at least be forced to make one. filter is _not_ supposed to mutate anything. so you'd have to create a new Array and/or NodeList, and put the filtered values back in. Even then, doing all this stuff for what is effectively one single copy that is likely to be insignificant at a performance level is, in my opinion, excessive. I just copy once and make the code clearer.

[megous → hombre_fatal]

I see it a lot with other iterables, too. People may like one liners and functional style more than a procedural `for (of)` construct, so they use `[...iterable].any_array_function(...)` everywhere, except when foced not to by async code :).

Might also have something to do with Redux and immutable patterns. (the use of spread operator in general)

[mr_toad → hombre_fatal]

Usually it’s because you want to use an array function like .filter() that isn’t implemented by the iterable itself.

[megous → mr_toad]

NodeList.prototype.filter = Array.prototype.filter;

and you can querySelectorAll('...').filter(el => ...) without any copies.