Set eslint rule for unused class methods in React component

问题

I am trying to set an eslint rule for methods in class that are never used. Like in the following react component I have a method unUsedMethod which is never used, but eslint does not show an error for it.

class Sample extends Component {
    unUsedMethod() {
        console.log('I am never used');
    }
    render() {
        return 'Hello!';
    }
}

My eslint file looks like this

{
    "parser": "babel-eslint",
    "env": {
        "browser": true,
        "es6": true,
        "node": true
    },
    "extends": ["eslint:recommended", "plugin:react/recommended"],
    "parserOptions": {
        "ecmaFeatures": {
            "experimentalObjectRestSpread": true,
            "jsx": true,
            "sourceType": "module",
            "allowImportExportEverywhere": false,
            "codeFrame": false
        },
        "sourceType": "module"
    },
    "plugins": [
        "react"
    ],
    "rules": {
        "indent": [2, 4, {"SwitchCase": 1, "ObjectExpression": "first"}],
        "linebreak-style": [
            "error",
            "unix"
        ],
        "semi": [
            "error",
            "always"
        ],
        "react/display-name": 0,
        "react/prop-types": 0, // Temporary
        "react/no-unescaped-entities": 0,
        "no-trailing-spaces": 1
    }
}

来源：https://stackoverflow.com/questions/46584642/set-eslint-rule-for-unused-class-methods-in-react-component