ESLint - "no-unused-vars" on function parameters within TypeScript Types/Interfaces

Question

I am currently getting a eslint warning on function parameters within Types or Interfaces .

Doing the following:

type Test = {
  fn: (param: string) => void
}

Results in the following warning:

'param' is defined but never used. Allowed unused args must match /^_/u.

Here's what my .eslintrc.json looks like:

{
  "root": true,
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "project": "tsconfig.json"
  },
  "env": {
    "node": true
  },
  "plugins": ["@typescript-eslint"],
  "extends": [
    "eslint:recommended",
    "plugin:@typescript-eslint/eslint-recommended",
    "plugin:@typescript-eslint/recommended",
    "plugin:prettier/recommended"
  ],
  "rules": {
    "@typescript-eslint/interface-name-prefix": "off",
    "@typescript-eslint/explicit-function-return-type": "off",
    "@typescript-eslint/explicit-module-boundary-types": "off"
  }
}

Package versions:

"eslint": "^7.23.0"
"@typescript-eslint/eslint-plugin": "^4.22.1"
"@typescript-eslint/parser": "^4.22.1"

Similar questions have been asked already here and here , but the provided answers do not seem to be doing it for me.

Any suggestions as to what could be happening?

Answer 1

I solved it this way, put these two lines in rules in the eslint configuration file.

"no-unused-vars": "off",
"@typescript-eslint/no-unused-vars": ["error"]

Answer 2

Instead of setting the no-unused-vars globally in your eslint config, you could set it to the line by placing this comment just above it:

 // eslint-disable-next-line @typescript-eslint/no-unused-vars

or to the entire file, just add this comment on the top:

/* eslint-disable @typescript-eslint/no-unused-vars */