microsoft / microsoft/TypeScript

Use ReadonlyArray<T> in type declarations

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Description

We can't really use ReadonlyArray anywhere else until we fix the type declarations.
This is technically a breaking change, but people shouldn't have been modifying arrays after creation anyway.

Contributor guide

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

No files, tests, or entry points are named. Locate the type declarations that currently expose mutable arrays, identify where ReadonlyArray should replace them, and verify that the affected declarations consistently prevent modification after creation without breaking their intended usage.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Refactor
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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