Must the optional chain end with .?propName?

[brad4d]

Would this be legal syntax?

maybeUndef?.method().prop = something;

[nicolo-ribaudo]

That would be valid: this proposal re-uses the existing optional chaining syntax with no additional restrictions other than "it cannot end with a function call". This is so that developers can re-using their existing knowledge about assignment to member expressions and about optional chaining, without having to remember that when used together there are arbitrary additional restrictions.

The readme shows expr1?.foo().prop[key] = val as an example.