Memoize call expressions in optional chains in loose mode

[oliverdunk]

Q	A
Fixed Issues?	Fixes #11084
Patch: Bug Fix?	Yes
Major: Breaking Change?	No
Minor: New Feature?	No
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?	No
License	MIT

Previously, in loose mode, we weren't memoizing optional call expressions. This resulted in code like a.get(b)?.(); being compiled to a.get(b) == null ? void 0 : a.get(b)();, which repeats a function call.

This MR changes the behaviour so that memoization is only skipped when no work is done by the call's callee.

[jridgewell]

I think we need more test here. Eg,

foo.bar()?.()
foo[bar]()?.()

foo.bar().baz?.()
foo[bar]().baz?.()

This will highlight a few more cases we're failing. To fix, we need to adjust the isCall checks below.

[oliverdunk]

@jridgewell Please ignore that request for review. I need to make sure we're probably setting the call context.

[jridgewell]

If you need help, here's another test case.

[oliverdunk]

@jridgewell Found and fixed my bug! It would be great if you could take a look :)

[jridgewell]

Almost there.

[oliverdunk]

@jridgewell I've addressed your feedback again. Really appreciate all of the help! It's early days when it comes to my understanding of Babel - but you and Nico have been incredibly welcoming.

[existentialism]

Nice work @oliverdunk!

[kaicataldo]

Thank you for contributing!

[nicolo-ribaudo]

Thanks Oliver!