Migrate from tslint to eslint

[eps1lon]

Looking for replacements of the following tslint rules:

• deprecation
• dtslint/no-relative-import-from-test

[tiuweehan]

Hi, I would like to look into this issue if it is available.

[joshwooding]

@tiuweehan Due to the “good to take” label I would say it’s available and feel free to investigate it.

[eps1lon]

An alternative to https://github.com/ibezkrovnyi/eslint-plugin-expect-type#readme might be https://github.com/4Catalyzer/eslint-plugin-ts-expect

[eps1lon]

Hopefully microsoft/TypeScript#36014 gets released. Then we could already switch from tslint to tsc. Should also help with overzealous IDEs that report a many issues in the repo (that are expected).

$ExpectType is a bit harder though.

[ExE-Boss]

For $ExpectType, I just use:

declare function expectType<T>(value: T): T;

from tsd.

[eps1lon]

With TypeScript 3.9 we'll be able to replace $ExpectError with @ts-expect-error. As soon as 3.9 is stable we can merge master...eps1lon:chore/remove-expect-error. Resolved in #21308

For $ExpectType we have to do a bit more research since I suspect that most solutions that test for assignability do not consider any. Done in #21309

There are some other rules where it's not obvious that eslint-typescript implements them:

• deprecation
• dtslint/no-relative-import-from-test

[dragos199993]

What is the status of this issue? I would like to start on this.
Thanks