ESLint with React gives `no-unused-vars` errors

I've setup eslint & eslint-plugin-react.

When I run ESLint, the linter returns no-unused-vars errors for each React component.

I'm assuming it's not recognizing that I'm using JSX or React syntax. Any ideas?

Example:

app.js

import React, { Component } from 'react';
import Header from './header.js';

export default class App extends Component {
  render() {
    return (
      <div>
        <Header />
        {this.props.children}
      </div>
    );
  }
}

Linter Errors:

/my_project/src/components/app.js
  1:8  error  'React' is defined but never used   no-unused-vars
  2:8  error  'Header' is defined but never used  no-unused-vars

Here is my .eslintrc.json file:

{
    "env": {
        "browser": true,
        "es6": true
    },
    "extends": "eslint:recommended",
    "parserOptions": {
        "ecmaFeatures": {
            "experimentalObjectRestSpread": true,
            "jsx": true
        },
        "sourceType": "module"
    },
    "plugins": [
        "react"
    ],
    "rules": {
        "react/jsx-filename-extension": [1, { "extensions": [".js", ".jsx"] }],
        "indent": [
            "error",
            2
        ],
        "linebreak-style": [
            "error",
            "unix"
        ],
        "quotes": [
            "error",
            "single"
        ],
        "semi": [
            "error",
            "always"
        ]
    }
}

In your .eslintrc.json, under extends, include the following plugin:

'extends': [
    'plugin:react/recommended'
]

Source

Mihey Mik

To solve this only problem without adding new rules from react/recommended install eslint-plugin-react:

npm i eslint-plugin-react --save

add in .eslintrc.js:

"plugins": ["react"]

and:

"rules": {   
     "react/jsx-uses-react": "error",   
     "react/jsx-uses-vars":
     "error" 
}

Since I found this while googling, you should know that this simple rule is enough to prevent this message:

react/jsx-uses-react

The react/recommended set of rules adds many other rules you may not want.

In my case I needed to add in your .eslintrc.js:

'extends': [
    'plugin:react/recommended'
]

plus a specific tweaking to rid of preact import: import { h } from 'preact' but you can use this example to get rid of your specific warnings like so:

    "no-unused-vars": [
        "error",
        {
            "varsIgnorePattern": "^h$"
        }
    ],

From this create-react-app github issue.

You could also add the following line above the first line:

// eslint-disable-next-line no-unused-vars
import React from 'react'

来源：https://stackoverflow.com/questions/42541559/eslint-with-react-gives-no-unused-vars-errors

标签

javascript

reactjs

jsx

eslint