In Intl we have this:

new Intl.NumberFormat('en', { minimumSignificantDigits: 3, maximumSignificantDigits: 3 }).format(0)
// "0.00"

I don't see an inconsistency here, as Intl.NumberFormat only formats with exponential notation if you ask for it:

new Intl.NumberFormat('en', { notation: 'scientific', minimumSignificantDigits: 2, maximumSignificantDigits: 2 }).format(450)
// "4.5E2"

At one point in the array slice notation proposal, I'd suggested a splice mechanism as well, i.e.:

ar[^1] = x; // set at ar.length-1
ar[^0] = x; // set at ar.length (i.e., push)
ar[^1:]; // get slice from ar.length-1 to end
ar[^0:]; // get slice from ar.length to end (e.g., empty)

ar[^0:] = ar2; // splice ar2 into ar at ar.length
ar[^1:] = ar2; // splice ar2 into ar at ar.length - 1
// etc.

fwiw I would guess pushFrom would be web-compat, https://github.com/search?q=%28language%3Ajs+OR+language%3Ats%29+%22.pushFrom%28%22&type=code

group had a conflict because it was a name you might put on other objects, and flatten had a conflict because it was an obvious name to use, but pushFrom is a pretty weird name to use unless you are following our language convention of "from = iterable"

unrelated to the meeting today, I suspect many here will be interested in this project, an object-capabilities-based RPC library for the web, including in particular pipelining https://blog.cloudflare.com/capnweb-javascript-rpc-library/

When you start an RPC, you get back a promise. Instead of awaiting it, you can immediately use the promise in dependent RPCs, thus performing a chain of calls in a single network round trip.

which rhymes with https://github.com/tc39/proposal-wavy-dot

this came up in real time as well, but isThenable in general is ill-advised because Promises/A+ requires a single Get of "then". So really you'd need something else anyway, e.g.

const snapshotThenable = value => {
  const then = !isPrimitive(value) && value.then;
  if (typeof then !== "function") return undefined;
  return { then: (...args) => Reflect.apply(then, value, args) };
};