Can rules use type information in their checking?

[aboyton]

One of the great features of TSLint is that you can use type information as part of your lint rules. https://palantir.github.io/tslint/usage/type-checking/

Is this possible with ESLint? An example of a rule that uses this (in addition to the 20 core rules marked "Requires Type Info") is the this custom lint rule that checks that any used RxJS operators are imported.

If I am to stop using TSLint (which I'd love to be able to do), then this is sadly a blocker for me.

[JamesHenry]

I created a working POC of this almost exactly a year ago: eslint/typescript-eslint-parser#61 (comment)

We have a bit more infrastructure available to us in ESLint parsers than we did then, so it should definitely be possible.

I am actively working with the rest of the ESLint Team to improve parser integrations and I will make sure this is considered.

[aboyton]

Awesome. I knew I'd seen a comment of yours previously about a proof of concept about this but couldn't find it. Let me know how I can be helping with this.

[j-f1]

@JamesHenry any updates on this?

[donaldpipowitch]

Hi there, is this proof of concept somehow useable already? Or are there other recommended workarounds to get the TypeScript type information into an Eslint rule? Thanks

[JasCodes]

This would actually made me move from tslint to this plugin

[j-f1]

There should be some useful things available in the parser services with new-ish versions of TS-ESLint-parser.

[armano2]

There is in typescript-eslint-parser with this: eslint/typescript-eslint-parser#568

For testing i wrote one rule with usage of it #230, we have to wait for new release of parser

[bradzacher]

closing in favour of #277 / #278