如何解决Next.js中Eslint no-unused-vars类型参数报错？

Problem #

I'm building a Next.js project with profile view, delete, and update features. I defined this type for my profile component's props:

type DeleteProfileParams = {
  // ESLint error: 'profile' is defined but never used. (no-unused-vars)
  onSuccess?: (profile: Profile) => void
}

When the delete operation succeeds, I call the parent-passed onSuccess function with the API's returned result. But ESLint throws a no-unused-vars error for the profile parameter. I don't want to disable the rule globally or per-line (even though line-disabling works), and I'm looking for a better approach. Here's my .eslint.json config:

{
 "env": {
    "browser": true,
    "es2021": true,
    "node": true
  },
  "parser": "@typescript-eslint/parser",
  "extends": [
    "plugin:@typescript-eslint/recommended",
    "next/core-web-vitals",
    "eslint:recommended",
    "plugin:react/jsx-runtime",
    "plugin:react/jsx-runtime",
    "prettier"
  ],
  "globals": {
    "React": "readonly"
  },
  "rules": {
    "@typescript-eslint/no-var-requires": "off"
  },
  "overrides": [
    {
      "files": [
        "*.test.{ts,tsx}",
        "src/testing/**/*.{ts,tsx}"
      ],
      "globals": {
        "it": "readonly",
        "describe": "readonly"
      },
      "rules": {
        "@typescript-eslint/no-explicit-any": "off",
        "@typescript-eslint/ban-ts-comment": "off"
      }
    }
  ]
}

Solutions #

• Prefix with underscore: Rename the parameter to _profile—TypeScript and ESLint recognize this as an intentionally unused parameter, suppressing the error:

  type DeleteProfileParams = {
    onSuccess?: (_profile: Profile) => void
  }
  

• Tweak ESLint rule configuration: Update your .eslint.json to ignore unused parameters marked with underscores, or adjust rules to fit your needs. Modify the rules section:

  "rules": {
    "@typescript-eslint/no-var-requires": "off",
    "@typescript-eslint/no-unused-vars": [
      "error",
      {
        "argsIgnorePattern": "^_",
        "varsIgnorePattern": "^_",
        "args": "all"
      }
    ]
  }
  

  This setup lets you use underscores to flag unused parameters without disabling the rule entirely.

Content sourced from Stack Exchange, question author: Liben Hailu