microsoft / microsoft/TypeScript
Allow subclass constructors without super() call
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Needs Proposal
Suggestion
- Dominant language
- Go
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Description
TypeScript Version:
1.8.0
Code
Custom element classes often have constructors that just return document.createElement(), since HTMLElement doesn't have a callable constructor, but this generates an error in TypeScript:
class MyElement extends HTMLElement {
constructor() {
return document.createElement('my-element');
}
}
In general, it is completely valid ES2015 to not call super(), as long as you don't access this.
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
No file or test is named in the issue. Start by locating the TypeScript diagnostic for derived constructors that omit super(), then add regression coverage for the HTMLElement example and verify that valid ES2015 constructors without super() or this access are accepted.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, typescript
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100