BUG "jsx-key" should warning when iterate element with optional chaining syntax

[JonathanLee-LX]

Iterate jsx element with optional chaining syntax, react/jsx-key rule don't show warnings.

Just like this

[JonathanLee-LX]

Maybe this example will be more accurate

[ljharb]

(in general, please post code samples as text; images of text are not accessible, can't be copy-pasted, and difficult to read in many circumstances)

That second example would never happen in real code, of course, but yes, I agree that in that case it should show a warning.

[JonathanLee-LX]

Thank you first, yes, in the second example, the initial value of arr is normally set to [] instead of undefined, so this rule is generally not a problem.

[JonathanLee-LX]

I cloned this repository, and try to add a test case like below
{ code: '[1, 2, 3]?.map(x => <App />)', parser: parsers.TYPESCRIPT_ESLINT, errors: [{message: 'Missing "key" prop for element in array.'}] }
This test case will fail, if add key in App, this case will pass。
So，TYPESCRIPT_ESLINT parser has already implemented this use case?

[ljharb]

perhaps - is that the parser you're using? only the typescript parser, and babel-eslint, currently support optional chaining.

[JonathanLee-LX]

I'm using @typescript-eslint/parser, the version is ^2.7.0.

[ljharb]

TYPESCRIPT_ESLINT is the old parser; you'll need '@TYPESCRIPT_ESLINT' for your failing test case. Want to make a PR with it?

[JonathanLee-LX]

Yes, I want, but I can't make this use case pass the test with @typescript-eslint/parser.

[ljharb]

That’s fine, a PR with a failing test is still much easier for me to work with than issue comments :-)