feat(core): Allow typeguards on QueryList.filter

[JeanMeche]

To match the behaviour of Array.filter, typeguards can now be used on QueryList.filter to narrow the return type.

Fixes #38446

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• angular.io application / infrastructure changes
• Other... Please describe:

Does this PR introduce a breaking change?

• Yes
• No

[JeanMeche]

I'm also thinking about including the fix for #39602 in this PR.

Edit: No need for that, it was fixed from TS 4.2 onwards.

[AndrewKushnir]

Just a quick note to myself: the typings for the Array.filter are here: https://github.com/microsoft/TypeScript/blob/main/lib/lib.es5.d.ts#L1256

[AndrewKushnir]

@JeanMeche thanks for the PR! I've checked that the typings of the QueryList.filter are similar to the typings of the Array.filter method.

This change might introduce a breaking change in apps code. The possibility is very low, so we probably won't need a schematic to migrate the code (we'll be able to tell precisely after running tests in Google's codebase), but we'd be able to include this change only into the next major version (v16) according to the SemVer. I've added this PR to the "v16-candidates" Github milestone and we'll get back to this PR once the main branch is open for v16 changes (which will happen after releasing the last v15.x minor version).

Thank you.

[AndrewKushnir]

Global Presubmit.

[pkozlowski-opensource]

@AndrewKushnir this look it is good to go, right?

[AndrewKushnir]

@pkozlowski-opensource yes, it should be ready for merge after one more TGP (just in case). Will update the PR once I have TGP results.

[AndrewKushnir]

Global Presubmit #2.

[AndrewKushnir]

Reviewed-for: fw-core, public-api

[jessicajaniuk]

reviewed-for: public-api

[AndrewKushnir]

Global Presubmit #3.

[alxhub]

Reviewed-for: public-api

[AndrewKushnir]

Caretaker note: TGP is "green", this PR is ready for merge.

[dylhunn]

This PR was merged into the repository by commit b2327f4.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}