LWN: Comments on "Firefox 74.0"

Firefox 74.0

lwn@pck.email — Thu, 12 Mar 2020 02:40:13 +0000

TC39 discussions are held in the open, all you'd ever probably want to know about why anything was done in a particular way can be found in the proposal and the surrounding comments:

https://github.com/tc39/proposal-optional-chaining

Firefox 74.0

dtlin — Wed, 11 Mar 2020 19:46:23 +0000

It's ?. in many other languages, such as C#, Groovy, Kotlin, Swift, and TypeScript. Python's PEP-505 proposal also used ?., although the other operators don't use ., for example ?[] and ?(). (IMO JS's ?.[] and ?.() reads a little oddly, since you don't use .[] or .() normally, but I'll get used to it eventually.)

Firefox 74.0

flussence — Wed, 11 Mar 2020 18:49:47 +0000

I'm somewhat confused why they went with "?." instead of the more regex-like mnemonic ".?" (which also has 20 years of prior art). Maybe it's meant to resemble PHP's "?:" operator?

Firefox 74.0

HelloWorld — Wed, 11 Mar 2020 18:04:09 +0000

Yeah, now if only something like that was available for other, similar kinds of computational structures. Maybe we could call it a ”Monad“.

Firefox 74.0

flussence — Tue, 10 Mar 2020 17:41:57 +0000

Javascript has a safe-call operator now, that's interesting.