microsoft / microsoft/TypeScript
Improve error message if JSX factory function is not imported
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Description
Bug Report
A colleague who is new to JSX recently wrote code equivalent to <div></div> (Playground link) and got this confusing error:
JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
Cannot find name 'React'.
But from my colleague's perspective, why would TypeScript be looking for "name 'React'"? It is not obvious from reading the code that it compiles to React.createElement('div') and that this requires an import.
I can imagine two possible solutions:
- Improve the error message, e.g. "JSX requires importing a factory function (configured as
React.createElementin this project) but that import is not present in this file." - Make the import unnecessary, e.g. introduce a new option to tell the compiler how to automatically add an import for the factory function if it's needed.
This is different than, but in the same general category as, other issues about JSX error messages like #42955 and #42794. I suspect this issue might not get enough priority to be addressed on its own, but maybe it could in the context of a small effort to improve JSX error messages in general.
🔎 Search Terms
JSX error message
🕗 Version & Regression Information
As far as I know, this has always happened. It at least happens in TS 4.3.
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about JSX.
⏯ Playground Link
Playground link with relevant code
💻 Code
<div></div>
🙁 Actual behavior
Received confusing error message described above.
🙂 Expected behavior
Received clear error message or no error.
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
Start with the linked Playground example and the JSX snippet to reproduce the current diagnostics, including the missing JSX.IntrinsicElements and React errors. The work is done when the example produces a clear factory-import diagnostic or no longer requires the import, with the chosen behavior reflected in relevant compiler tests.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- react, typescript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 28/100