1519482 - [META] Function implementation hiding proposal

Status: NEW

(Core :: JavaScript Engine, enhancement, P3)

Description

[Alexandre Folle de Menezes]

The proposal is currently in Stage 2.

Comment 1

[Jason Orendorff [:jorendorff]]

Thoughts:

1. It seems to me the motivation for this proposal is unusually weak, even for TC39.

   • The main justification for this is Angular abusing Function.prototype.toString. But the feature does not actually address that problem. It just puts a "break Angular" directive into the language. Maybe it should be called "punish the impure";. Or "use no evil";. :P

   • Also mentioned: Two polyfill authors have developed workarounds to trick _.isNative(). But we shouldn't add features to JS for the benefit of those two people, especially since they already have a way to fool _.isNative that works. So what problem is this solving, again?

2. Setting aside the behavior change, developers (and compile-to-JS folks) will be interested in memory savings and that is probably the main reason (if any) they'll want to use this. But we currently retain source code on a per-script basis, not per-function, so if we implement this in the obvious way, they won't actually save any memory when using this directive in a function prologue.

3. If we do in fact discard source, it would affect the debugger. Quality-of-life thing, but the devtools team will want to think about this, if this proposal sticks.

Comment 2

[Alexandre Folle de Menezes]

The proposal is now called "Function implementation hiding", updating the bug title and link accordingly.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The meta keyword is there, the bug doesn't depend on other bugs and there is no activity for 12 months.
:willyelm, maybe it's time to close this bug?

Comment 4

[Steven DeTar [:sdetar]]

This should still stay open, it is still a Stage 2 proposal in TC39.