Implementation status

[chicoxyzzy]

• - V8 / Chrome 69
• - SpiderMonkey / Firefox 62
• - JSC / Safari 12
• - ChakraCore / Edge 19 probably

[keithamus]

ChakraCore issue chakra-core/ChakraCore#5543

[chicoxyzzy]

ChakraCore PR chakra-core/ChakraCore#5573

[chicoxyzzy]

@bterlson @michaelficarra all major browsers has implemented these features. test262 already have tests (flat, flatMap). It seems that proposal needs just PR to ecma262 to become ES2019

[ljharb]

It’d also need committee consensus.

[chicoxyzzy]

It could be too late for consensus when most of browsers will start to ship it on by default.

• Chrome 69 will be released on September 4
• Firefox 62 will be released on September 5
• Safari 12 will be released on September 12 presumably

While next TC39 meeting will happen on September 25

[ljharb]

I’m not sure what you mean by “too late”; stage 4 requires 1-2 shipping implementations minimum (at which point it’s web incompatible to unship it), but there’s no maximum.

[chicoxyzzy]

Oh. I though that by consensus you mean something like approvement from committee. That unshipping compatibility rule makes sense to me.

[ljharb]

Yes, the committee needs to officially approve stage 4 as well.

[chicoxyzzy]

So if feature won't be approved in the time when it will be shipped in most browsers then it won't go to spec. Though browsers can't unship this feature. Probably other environments will also ship that unspecced feature to make it possible to port code which works on those browsers to their platform. It seems like a big problem. Not sure I understand you correctly though

[ljharb]

I think you do; that something can’t be removed isn’t the same thing as that thing being in the spec, because that requires consensus. It’s all in the process document.

[tschneidereit]

This is correct in principle, as the TC39 process requires explicit committee approval for stage advancement. In practice, this is a rubber stamp and an opportunity to do a round of applause in a committee meeting :)

[michaelficarra]

Championing a proposal is (most of the time) a whole lot of work, and that round of applause means a lot. Looking forward to finally putting a bow on this one.