[valid-mock-module-path] does not work with typescript path aliases

[atheck]

Having path aliases in the tsconfig.json file, like:

// ...
  "paths": {
      "@lib/*": [
        "./path/to/lib/*"
      ],
  }
// ...

the "valid-mock-module-path" rule flags a call to `jest.mock("@lib/someModule");`.

I think this is a false positive.

[G-Rath]

yup we totally should support a aliases kind of option

[hainenber]

Appreciate the rule usage @atheck!

@G-Rath implementation wise, I wonder what would be the most proper approach for this issue? Should we have a rule option like aliases, duplicating the config? Or we should rely on typescript installation to do the needful, making the rule bit more cumbersome by looping in TS machineries?

[atheck]

I think it should be an option because bundlers like babel and webpack also support aliases. So you can use aliases without typescript and eslint can't know where to look for the correct aliases configuration. I think copying the configuration would be fine here.

[G-Rath]

yeah what @atheck said, especially since going forward ESLint configs are always JS it should be trivial for people to pass through their options e.g. require('./tsconfig.json').

The option we're actually mirroring here is the moduleNameMapper, though we can just start with a simple Record<string, string> (it might be useful to support regexps, but again people can do logic in their config files, and it's a breaking change for us to change that feature afterwards, so lets stick with just strings for now).

I would expect if we ever supporting reading Jest config files, we'd use that property by default

tl;dr start with a Record<string, string> which we can just "if (p in aliases)" as part of the rule

[jerone]

Automatic detection for aliases would have my preference. The less configuration on double places the better.

We are using another ESLint plugin that detects tsconfig.json and jsconfig.json aliases automatically. In this case for imports. Maybe you can find inspiration from this package: https://github.com/Limegrass/eslint-plugin-import-alias