如何使用 React 设置 Eslint

Question

I'm using webpack with React and Eslint, I have set the extends on Eslint, however, it still says 'React' is defined but never used.eslintno-unused-vars

This is my.eslintrc file:

{
    "parser": "babel-eslint",
    "extends": ["eslint:recommended", "plugin:react/recommended", "airbnb", "prettier"],
    "parserOptions": {
        "sourceType": "module",
        "ecmaVersion": 2015
    },
    "env": {
        "browser": true,
        "node": true,
        "jest": true,
        "commonjs": true
    },
    "rules": {
        "react/jsx-uses-react": "error",
        "react/jsx-uses-vars": "error",
        "react/jsx-filename-extension": [1, { "extensions": [".js", ".jsx"] }],
        "linebreak-style": "off",
        "no-undef": "off",
        "no-debugger": "off",
        "no-alert": "off",
        "indent": ["error", 4],
        "quotes": "off",
        "no-console": "off"
    }
}

React version is ^17.0.1

babel-eslint is ^10.1.0

eslint is ^7.14.0

eslint-plugin-react is ^7.21.5

Answer 1

Looks like it has to do with actual JSX in the file

Your config worked fine on a file that actually contains valid JSX:

// App.jsx
import React from 'react'; // 
const App = () => {
    return <div />; // JSX
}

export default App

But if no JSX is found in the file it throws the error you described:

// App.jsx
import React from 'react'; // 'React' is defined but never used 
const App = () => {
    return 1; // no JSX
}

export default App