Just a note: Please be conservative about using this in m-c while it's not
enabled in release yet, to avoid issues when uplifting patches. Otherwise,
I think this is a great new feature that I'd love to use.

On Wed, Jan 22, 2020 at 4:30 PM Patrick Brosset <pbros...@mozilla.com>
wrote:

> Thanks Yulia, this is going to be very useful and helpful in reducing code
> complexity!
>
> For info, here's a DevTools bug to make sure the console panel still
> supports autocompletion even when ?. is used:
> https://bugzilla.mozilla.org/show_bug.cgi?id=1594009
> I also a question: do you know if eslint is ready for this new syntax? In
> other words, can we use it in m-c without causing eslint parsing errors?
>
> On Tue, Jan 21, 2020 at 8:11 PM Yulia Startsev <yu...@mozilla.com> wrote:
>
> > Hi,
> >
> > In Firefox 74, we'll ship the optional chaining operator.
> >
> > *Bug: *https://bugzilla.mozilla.org/show_bug.cgi?id=1566143
> > *Standard: *https://tc39.es/proposal-optional-chaining/
> > *Platform coverage: *All, no pref
> > *DevTools bug: *N/A.
> > *Other browsers:* Shipping in Chrome, Shipping in Safari
> > *Testing: *
> >
> >
> https://github.com/tc39/test262/tree/master/test/language/expressions/optional-chaining
> > <
> >
> https://github.com/tc39/test262/tree/master/test/language/expressions/coalesce
> > >
> >
> > *Use cases: *Optional chaining may be useful in cases where a property
> may
> > be conditionally present. This affects property access, dynamic property
> > access, and function calls in the following way:
> >
> > *Property access*
> >
> > Before
> > const street = user.address && user.address.street;
> >
> > After
> > const street = user.address?.street;
> >
> > *Dynamic Property Access*
> > Before
> > const street = user.address && user.address["street"];
> >
> > After
> > const street = user.address?.["street"];
> >
> > *Optional function calls:*
> >
> > Before
> > const result = myObj.method && myObj.method();
> >
> > After
> > const result = myObj?.method();
> >
> >
> > *Secure contexts:* This is a JS language feature and is therefore present
> > in all contexts.
> > _______________________________________________
> > dev-platform mailing list
> > dev-platform@lists.mozilla.org
> > https://lists.mozilla.org/listinfo/dev-platform
> >
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