Add 2023 array methods to target features

[OliverRadini]

Fixes #52220

Adds es2023 array methods to target features.

I haven't added any unit tests for this - I couldn't find anything that tests this already, and I'm afraid I don't know enough about the repo to determine where these would make sense. Any pointers would be much appreciated :)

[Tobias-Scholz]

@OliverRadini - Take a look at indexAt.ts. You would need to write a similar file for findLastIndex and findLast.

[OliverRadini]

@tobeyyyyy brilliant, thanks - I'll take a look and add that in

[OliverRadini]

@tobeyyyyy Just taken a look, slightly confused though as it seems as though it may already be covered by the tests in findLast.ts. I'm probably getting things confused but I'm not sure what I'd add additionally to that.

[Tobias-Scholz]

@OliverRadini - Ah, was not aware that a file like that already exists. The first line of the file defines all the targets for which baselines will be created. Right now, the only target in findLast.ts is esnext. You could now add es2022 to this list. Running the tests would generate a baseline like indexAt(target=es2021).errors.txt which includes the error message.

[OliverRadini]

@tobeyyyyy ah brilliant, thanks. I amended the line as suggested and indeed did see the errors as expected. Is this the normal behaviour for the tests? I added the line, but now there are failing tests. I suppose I don't quite yet understand the workflow. The errors I get are:

tests/cases/compiler/findLast.ts(1,44): error TS2550: Property 'findLast' does not exist on type 'number[]'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2023' or later.
tests/cases/compiler/findLast.ts(2,51): error TS2550: Property 'findLast' does not exist on type 'string[]'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2023' or later.
tests/cases/compiler/findLast.ts(3,17): error TS2550: Property 'findLast' does not exist on type 'Int8Array'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2023' or later.

etc.

So, what I would expect to see after the change I added on a version which doesn't yet have findLast. Is this the expected behaviour?

[Jack-Works]

Run > npx hereby baseline-accept

[OliverRadini]

@microsoft-github-policy-service agree

[OliverRadini]

@Jack-Works Great, thanks - ran that and all good now. Thanks for the help

[OliverRadini]

Hopefully this is in a better state now, once I figured out a bit more about how the baseline stuff works 😂