feat: add iterator methods to esnext

[Oleksandr Tarasiuk (a-tarasyuk)]

Fixes #63700

[Copilot]

Pull request overview

Adds ESNext declarations for recent iterator proposals and integrates the new library into compiler resolution and bundling.

Changes:

• Adds chunks, join, includes, zip, and zipKeyed declarations.
• Registers and embeds lib.esnext.iterator.d.ts.
• Adds compiler tests and updates generated baselines.

Reviewed changes

Copilot reviewed 35 out of 40 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tsc/internal/bundled/embed_generated.go	Embeds the new iterator library.
tsc/internal/bundled/libs/lib.esnext.d.ts	References the iterator library.
tsc/internal/bundled/libs/lib.esnext.iterator.d.ts	Declares the new iterator APIs.
tsc/internal/bundled/libs_generated.go	Registers the bundled library name.
tsc/internal/compiler/program_test.go	Adds the library to ESNext test expectations.
tsc/internal/tsoptions/enummaps.go	Maps esnext.iterator to the new library.
tsc/testdata/tests/cases/compiler/iteratorChunks.ts	Tests Iterator.prototype.chunks.
tsc/testdata/tests/cases/compiler/iteratorIncludes.ts	Tests Iterator.prototype.includes.
tsc/testdata/tests/cases/compiler/iteratorJoin.ts	Tests Iterator.prototype.join.
tsc/testdata/tests/cases/compiler/iteratorZip.ts	Tests Iterator.zip and zipKeyed.
tsc/testdata/baselines/reference/compiler/iteratorChunks.js	Records chunks emit.
tsc/testdata/baselines/reference/compiler/iteratorChunks.symbols	Records chunks symbols.
tsc/testdata/baselines/reference/compiler/iteratorChunks.types	Records chunks types.
tsc/testdata/baselines/reference/compiler/iteratorIncludes.js	Records includes emit.
tsc/testdata/baselines/reference/compiler/iteratorIncludes.symbols	Records includes symbols.
tsc/testdata/baselines/reference/compiler/iteratorIncludes.types	Records includes types.
tsc/testdata/baselines/reference/compiler/iteratorJoin.js	Records join emit.
tsc/testdata/baselines/reference/compiler/iteratorJoin.symbols	Records join symbols.
tsc/testdata/baselines/reference/compiler/iteratorJoin.types	Records join types.
tsc/testdata/baselines/reference/compiler/iteratorZip.js	Records zip emit.
tsc/testdata/baselines/reference/compiler/iteratorZip.symbols	Records zip symbols.
tsc/testdata/baselines/reference/compiler/iteratorZip.types	Records zip types.
tsc/testdata/baselines/reference/compiler/builtinIterator.symbols	Updates merged iterator symbols.
tsc/testdata/baselines/reference/compiler/builtinIterator.types	Updates displayed iterator signatures.
tsc/testdata/baselines/reference/compiler/libReplacement(libreplacement=true).trace.json	Records replacement lookup for the new library.
tsc/testdata/baselines/reference/conformance/awaitUsingDeclarationsWithIteratorObject.symbols	Updates merged iterator symbols.
tsc/testdata/baselines/reference/conformance/awaitUsingDeclarationsWithIteratorObject.types	Updates displayed iterator signatures.
tsc/testdata/baselines/reference/conformance/usingDeclarationsWithIteratorObject.symbols	Updates merged iterator symbols.
tsc/testdata/baselines/reference/conformance/usingDeclarationsWithIteratorObject.types	Updates displayed iterator signatures.
tsc/testdata/baselines/reference/tsc/commandLine/Initialized-TSConfig-with-incorrect-compiler-option-value.js	Updates valid-library diagnostics.
tsc/testdata/baselines/reference/tsc/commandLine/help-all.js	Updates library help output.
tsc/testdata/baselines/reference/tsc/commandLine/help.js	Updates library help output.
tsc/testdata/baselines/reference/tsc/commandLine/show-help-with-ExitStatus.DiagnosticsPresent_OutputsSkipped-when-host-cannot-provide-terminal-width.js	Updates library help output.
tsc/testdata/baselines/reference/tsc/commandLine/show-help-with-ExitStatus.DiagnosticsPresent_OutputsSkipped.js	Updates wrapped library help output.
tsc/testdata/baselines/reference/tsc/ignoreConfig/without-any-options-when-config-file-absent-with---ignoreConfig.js	Updates library help output.
tsc/testdata/baselines/reference/tsc/ignoreConfig/without-any-options-when-config-file-absent.js	Updates library help output.
tsc/testdata/baselines/reference/tsc/showConfig/Show-TSConfig-with-incorrect-compiler-option-value.js	Updates valid-library diagnostics.
tsc/testdata/baselines/reference/tscWatch/commandLine/Parse-watch-interval-option-without-tsconfig.json.js	Updates library help output.
tsc/testdata/baselines/reference/tscWatch/commandLineWatch/watch-handles-tsconfig-deleted.js	Updates watched help output.
tsc/testdata/baselines/reference/tsoptions/commandLineParsing/parseCommandLine/Parse invalid option of library flags.js	Updates valid-library diagnostics.

Files not reviewed (3)

• tsc/internal/bundled/embed_generated.go: Generated file
• tsc/internal/bundled/libs_generated.go: Generated file
• tsc/testdata/baselines/reference/tsc/commandLine/Initialized-TSConfig-with-incorrect-compiler-option-value.js: Generated file

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[Daniel Rosenwasser (DanielRosenwasser)]

I don't know if you need to add a bunch more overloads yet, but I think there are a few places that can be simplified for now.

[Copilot]

🟡 Changes recommended

The empty-object zipKeyed case has an incorrect element type and lacks coverage.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

Files not reviewed (3)

• tsc/internal/bundled/embed_generated.go: Generated file
• tsc/internal/bundled/libs_generated.go: Generated file
• tsc/testdata/baselines/reference/tsc/commandLine/Initialized-TSConfig-with-incorrect-compiler-option-value.js: Generated file

• Files reviewed: 38/44 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[Copilot]

🔵 Needs a closer look

The declarations accept guaranteed-throw primitive inputs, reject valid undefined-valued keyed inputs, and incompletely validate union inputs.

Review details

Files not reviewed (3)

• tsc/internal/bundled/embed_generated.go: Generated file
• tsc/internal/bundled/libs_generated.go: Generated file
• tsc/testdata/baselines/reference/tsc/commandLine/Initialized-TSConfig-with-incorrect-compiler-option-value.js: Generated file

• Files reviewed: 38/44 changed files
• Comments generated: 0 new
• Review effort level: Balanced