microsoft / microsoft/TypeScript
Flag to type `Promise.catch` variables as `unknown`
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Suggestion
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- Go
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Description
Suggestion
✅ Viability Checklist
My suggestion meets these guidelines:
- This wouldn't be a breaking change in existing TypeScript/JavaScript code
- This wouldn't change the runtime behavior of existing JavaScript code
- This could be implemented without emitting different JS based on the types of the expressions
- This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
- This feature would agree with the rest of TypeScript's Design Goals.
⭐ Suggestion
Following #41016 a flag was added to consider catch variables as unknown.
For consistency and since they're similar cases, I suggest also adding a flag that does this for .catch callbacks on promises.
See also: eslint-plugin-etc/no-implicit-any-catch
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
The issue names no repository files or tests. Start by reading the existing catch-variable change referenced in #41016, then compare it with the Promise.catch callback behavior and the linked eslint rule. Done means a reviewed flag design and corresponding implementation and tests that type these callback variables as unknown.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 30/100