New eslint errors with the @typescript-eslint/no-unsafe-* rules

Question

I'm having some trouble with adding them into some existing projects. For example, I have a class in a module that I developed:

export default class ClassName {
  // Class members
}

Now I import that into another project:

import ClassName from 'modulename';

const object = new ClassName();

I get 2 errors on this line.

On the object in const object:

error  Unsafe assignment of an any value                @typescript-eslint/no-unsafe-assignment

On the new in new ClassName:

error  Unsafe construction of an any type value         @typescript-eslint/no-unsafe-call

How can I avoid these errors?! I would really like to be able to follow these rules because I think they'd be so useful!

Thanks.

---

Here's another example:

import { readJsonSync } from 'fs-extra';
const testEnv = readJsonSync(testEnvPath);

Here I get the no-unsafe-assignment error on the testEnv of const testEnv, and the no-unsafe-call error on the readJsonSync call on the second line.

I can get rid of the first one with this code:

interface ITestEnv {
  // interface members
}
const testEnv: ITestEnv = readJsonSync(testEnvPath) as ITestEnv;

however, I still can't figure out how to get rid of the second one on the readJsonSync call.

Answer 1

In the first case, you have just one error coming from the constructor, which is cascading to the const assignment. Something in your class implementation is making the type-inference to be inferred as any.

Not saying your code is incorrect. It might be, but there's an (open issue on Github) reporting a constructor as being incorrectly flagged by the same rule.

On your second issue, have you added @type/fs-extra as a project dependency? Many npm packages do not have types themselves. Types are created by someone and added to the @types library. When that's the case, the @types/package_name must be added as a dependency separately.