TC39 Decimal_Measure on 2025-04-14

18:32	<nicolo-ribaudo>	Do you think it would it be backward compatible for Intl to check if the argument to `.format()` has a `.significantDigits`/`.unit` property, rather just checking for the internal slot?
18:32	<nicolo-ribaudo>	For some delegates it's important to try to not check internal slots other than on the `this` argument, so that the feature does not break with membranes
18:36	<ljharb>	while i agree with their motivations i think it's reasonable for static methods to check slots on arguments, altho no precedent has been set
18:55	<littledan>	yeah, I think this would make plenty of sense -- maybe we could do it in https://tc39.es/ecma402/2024/#sec-tointlmathematicalvalue for the case ToPrimitive would've thrown an error from no method existing
20:43	<eemeli>	If we have `.format()` check for properties, then what's the decimal-proposal need for something like `Decimal.Amount` to exist at all? Could a `Decimal.p.toAmount()` return something like `{ valueOf: () => 42, significantDigits: 3 }`
22:45	<sffc>	eemeli: An intrinsic gives us immutability, ability to attach methods such as toString and toLocaleString, constructors, brand checking. I don't see why not to return an intrinsic from that method.