Description
Currently, to stay aligned with native JavaScript, you can migrate a JavaScript project to TypeScript just by switching to .ts files and everything should be OK (except if there are real errors).
But you're not in strict mode, which is what you want if you come to TypeScript.
Now that JSDoc is understood by TypeScript, and following #18747, it would help TypeScript adoption a lot to have a tool to refactor a full JavaScript project, correctly commented with JSDoc, to TypeScript (applying #18747 quickfix everywhere).
It could even include the conversion from .js to .ts extension.
It would mean we can automatically migrate from a JS project to real TypeScript (aka strict mode).