microsoft / microsoft/TypeScript
Request: Class Decorator Mutation
Open
Nobody has claimed this yet.
Needs Proposal
Suggestion
- Dominant language
- Go
- Stars
- 111k
- Forks
- 14.3k
- Avg merge
- 2d 4h
- Merged PRs (30d)
- 132
Description
If we can get this to type check properly, we would have perfect support for boilerplate-free mixins:
declare function Blah<T>(target: T): T & {foo: number}
@Blah
class Foo {
bar() {
return this.foo; // Property 'foo' does not exist on type 'Foo'
}
}
new Foo().foo; // Property 'foo' does not exist on type 'Foo'
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
Use the decorator and class examples in the issue as the starting entry point, and investigate how decorator return types relate to class instance types. Define tests covering the reported errors on Foo and new Foo().foo; done means the intended mixin properties type-check without regressing decorator behavior.
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
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100