.eslintrc.js

// module.exports = {
//     root: true,
//     parserOptions: {
//         parser: 'babel-eslint',
//         sourceType: 'module'
//     },
//     env: {
//         browser: true,
//     },
//     extends: [
//         'plugin:vue/essential', 
//         'standard',
//         'plugin:import/errors',
//     ],
//     // required to lint *.vue files
//     plugins: [
//         'vue'
//     ],
//     // check if imports actually resolve
//     'settings': {
//         'import/resolver': {
//             'webpack': {
//                 'config': 'build/webpack.base.conf.js'
//             }
//         }
//     },
//     // add your custom rules here
//     'rules': {
//         // allow debugger during development
//         'no-debugger': process.env.NODE_ENV === 'production' ? 2 : 0,
//         /*
//          * Possible Errors
//          */

//         // disallow unnecessary parentheses
//         'no-extra-parens': ['error', 'all', {'nestedBinaryExpressions': false}],

//         // disallow negating the left operand of relational operators
//         'no-unsafe-negation': 'error',

//         // enforce valid JSDoc comments
//         // 'valid-jsdoc': 'off',

//         /*
//          * Best Practices
//          */

//         // enforce return statements in callbacks of array methods
//         'array-callback-return': 'error',

//         // enforce consistent brace style for all control statements
//         curly: ['error', 'multi-line'],

//         // enforce consistent newlines before and after dots
//         'dot-location': ['error', 'property'],

//         // enforce dot notation whenever possible
//         'dot-notation': 'error',

//         // require the use of === and !==
//         'eqeqeq': ['error', 'smart'],

//         // disallow the use of arguments.caller or arguments.callee
//         'no-caller': 'error',

//         // disallow empty functions
//         'no-empty-function': 'error',

//         // disallow unnecessary calls to .bind()
//         'no-extra-bind': 'error',

//         // disallow unnecessary labels
//         'no-extra-label': 'error',

//         // disallow leading or trailing decimal points in numeric literals
//         'no-floating-decimal': 'error',

//         // disallow assignments to native objects or read-only global variables
//         'no-global-assign': 'error',

//         // disallow the use of eval()-like methods
//         'no-implied-eval': 'error',

//         // disallow the use of the __iterator__ property
//         'no-iterator': 'error',

//         // disallow unnecessary nested blocks
//         'no-lone-blocks': 'error',

//         // disallow multiple spaces
//         'no-multi-spaces': 'error',

//         // disallow new operators with the String, Number, and Boolean objects
//         'no-new-wrappers': 'error',

//         // disallow octal escape sequences in string literals
//         'no-octal-escape': 'error',

//         // disallow the use of the __proto__ property
//         'no-proto': 'error',

//         // disallow comparisons where both sides are exactly the same
//         'no-self-compare': 'error',

//         // disallow throwing literals as exceptions
//         'no-throw-literal': 'error',

//         // disallow unused expressions
//         'no-unused-expressions': 'error',

//         // disallow unnecessary calls to .call() and .apply()
//         'no-useless-call': 'error',

//         // disallow unnecessary concatenation of literals or template literals
//         'no-useless-concat': 'error',

//         // disallow unnecessary escape characters
//         'no-useless-escape': 'error',

//         // disallow void operators
//         'no-void': 'error',

//         // require parentheses around immediate function invocations
//         'wrap-iife': 'error',

//         // require or disallow “Yoda” conditions
//         yoda: 'error',

//         /*
//          * Variables
//          */
//         'no-unused-vars': 'warn',
//         'no-new': 'off',
//         // disallow labels that share a name with a variable
//         'no-label-var': 'error',

//         // disallow initializing variables to undefined
//         'no-undef-init': 'error',
//         'no-undef': 'off',
//         // disallow the use of variables before they are defined
//         'no-use-before-define': 'error',

//         /*
//          * Node.js and CommonJS
//          */

//         // disallow new operators with calls to require
//         'no-new-require': 'error',

//         /*
//          * Stylistic Issues
//          */

//         // enforce consistent spacing inside array brackets
//         'array-bracket-spacing': 'error',

//         // enforce consistent spacing inside single-line blocks
//         'block-spacing': 'error',

//         // enforce consistent brace style for blocks
//         'brace-style': ['error', '1tbs', {'allowSingleLine': true}],

//         // require or disallow trailing commas
//         'comma-dangle': 'error',

//         // enforce consistent spacing before and after commas
//         'comma-spacing': 'error',

//         // enforce consistent comma style
//         'comma-style': 'error',

//         // enforce consistent spacing inside computed property brackets
//         'computed-property-spacing': 'error',

//         // require or disallow spacing between function identifiers and their invocations
//         'func-call-spacing': 'error',

//         // enforce consistent indentation
//         'indent': ['error', 2, {SwitchCase: 1}],

//         // enforce the consistent use of either double or single quotes in JSX attributes
//         'jsx-quotes': 'error',

//         // enforce consistent spacing between keys and values in object literal properties
//         'key-spacing': 'error',

//         // enforce consistent spacing before and after keywords
//         'keyword-spacing': 'error',

//         // enforce consistent linebreak style
//         'linebreak-style': 'off',

//         // require or disallow newlines around directives
//         'lines-around-directive': 'error',

//         // require constructor names to begin with a capital letter
//         'new-cap': 'off',

//         // require parentheses when invoking a constructor with no arguments
//         'new-parens': 'error',

//         // disallow Array constructors
//         'no-array-constructor': 'error',

//         // disallow Object constructors
//         'no-new-object': 'error',

//         // disallow trailing whitespace at the end of lines
//         'no-trailing-spaces': 'error',

//         // disallow ternary operators when simpler alternatives exist
//         'no-unneeded-ternary': 'error',

//         // disallow whitespace before properties
//         'no-whitespace-before-property': 'error',

//         // enforce consistent spacing inside braces
//         'object-curly-spacing': ['error', 'always'],

//         // require or disallow padding within blocks
//         'padded-blocks': ['error', 'never'],

//         // require quotes around object literal property names
//         'quote-props': ['error', 'as-needed'],

//         // enforce the consistent use of either backticks, double, or single quotes
//         'quotes': ['error', 'single'],

//         // enforce consistent spacing before and after semicolons
//         'semi-spacing': 'error',

//         // require or disallow semicolons instead of ASI
//         // semi: ['error', 'never'],

//         // enforce consistent spacing before blocks
//         'space-before-blocks': 'error',

//         // allow console during development
//         'no-console': 'warn',

//         // enforce consistent spacing before function definition opening parenthesis
//         'space-before-function-paren': ['error', 'never'],

//         // enforce consistent spacing inside parentheses
//         'space-in-parens': 'error',

//         // require spacing around infix operators
//         'space-infix-ops': 'error',

//         // enforce consistent spacing before or after unary operators
//         'space-unary-ops': 'error',

//         // enforce consistent spacing after the // or /* in a comment
//         'spaced-comment': 'error',

//         // require or disallow Unicode byte order mark (BOM)
//         'unicode-bom': 'error',


//         /*
//          * ECMAScript 6
//          */

//         // require braces around arrow function bodies
//         'arrow-body-style': 'error',

//         // require parentheses around arrow function arguments
//         'arrow-parens': ['error', 'as-needed'],

//         // enforce consistent spacing before and after the arrow in arrow functions
//         'arrow-spacing': 'error',

//         // enforce consistent spacing around * operators in generator functions
//         'generator-star-spacing': ['error', 'after'],

//         // disallow duplicate module imports
//         'no-duplicate-imports': 'error',

//         // disallow unnecessary computed property keys in object literals
//         'no-useless-computed-key': 'error',

//         // disallow unnecessary constructors
//         'no-useless-constructor': 'error',

//         // disallow renaming import, export, and destructured assignments to the same name
//         'no-useless-rename': 'error',

//         // require let or const instead of var
//         'no-var': 'error',

//         // require or disallow method and property shorthand syntax for object literals
//         'object-shorthand': 'error',

//         // require arrow functions as callbacks
//         'prefer-arrow-callback': 'error',

//         // require const declarations for variables that are never reassigned after declared
//         'prefer-const': 'error',

//         // disallow parseInt() in favor of binary, octal, and hexadecimal literals
//         'prefer-numeric-literals': 'error',

//         // require rest parameters instead of arguments
//         'prefer-rest-params': 'error',

//         // require spread operators instead of .apply()
//         'prefer-spread': 'error',

//         // enforce spacing between rest and spread operators and their expressions
//         'rest-spread-spacing': 'error',

//         // require or disallow spacing around embedded expressions of template strings
//         'template-curly-spacing': 'error',

//         'no-tabs': 'warn',

//         // require or disallow spacing around the * in yield* expressions
//         'yield-star-spacing': 'error',

//         // Vue
//         'vue/html-indent': ["error", 2, {
//             "attribute": 1,
//             "closeBracket": 1,
//             "alignAttributesVertically": true,
//             "ignores": []
//         }]
//     }
// }


// https://eslint.org/docs/user-guide/configuring

module.exports = {
    root: true,
    parserOptions: {
      parser: 'babel-eslint'
    },
    env: {
      browser: true,
    },
    extends: [
      // https://github.com/vuejs/eslint-plugin-vue#priority-a-essential-error-prevention
      // consider switching to `plugin:vue/strongly-recommended` or `plugin:vue/recommended` for stricter rules.
      'plugin:vue/essential', 
      // https://github.com/standard/standard/blob/master/docs/RULES-en.md
      'standard'
    ],
    // required to lint *.vue files
    plugins: [
      'vue'
    ],
    // add your custom rules here
    rules: {
      // allow async-await
      'generator-star-spacing': 'off',
      // allow debugger during development
      'no-debugger': process.env.NODE_ENV === 'production' ? 'error' : 'off'
    }
  }