Why ESLint throws 'no-unused-vars' for TypeScript interface?

Question

So, I have this piece of code in .ts file:

import {MicroEventInterface} from '../Interfaces';  export default class MicroEvent implements MicroEventInterface {  // code 

And ESLint throws this error:

I have this config for TypeScript in ESLint:

typescript: {     extends: [         'plugin:@private/private/react' // private rep with React config     ],     parser: '@typescript-eslint/parser',     plugins: [         '@typescript-eslint',         'import'     ],     settings: {         'import/resolver': {             'node': {                 'extensions': [                     '.js',                     '.jsx',                     '.ts',                     '.tsx'                 ],                 'moduleDirectory': [                     'node_modules/',                     'src/'                 ]             }         },         react: {             createClass: 'createClass',             pragma: 'React',             version: '0.14.9'         }     } } 

So, everything seems like fine, but I can't conquer this error.

Any suggestions?

Thanks!

UPD:

Looks like if I console.log( --- , MicroEventInterface); error disappears. I think, ESLint does not treat implements as actual usage.

Answer 1

Source: I am the maintainer of the typescript-eslint project.

The latest version of the @typescript-eslint tooling now has full support for scope analysis.

So the steps to fix this are now:

• update your versions to at least v4.9.1 of @typescript-eslint/parser and @typescript-eslint/eslint-plugin
• update your ESLint version to at least v6.0.0
• update your config to use @typescript-eslint/no-unused-vars
  • Do not use the base no-unused-vars rule - see this FAQ article in the project.

Restart your IDE and you should now see the correct lint errors.

Answer 2

Use @typescript-eslint/no-unused-vars-experimental and turn off @typescript-eslint/no-unused-vars.

The issue is resolved in the latter version (experimental).

Sample config:

// .eslintrc {   ...   "rules": {     "@typescript-eslint/no-unused-vars": "off",     "@typescript-eslint/no-unused-vars-experimental": "error"   }   ... }