.eslintrc.js

module.exports = {
    root: true,
  
    parser: "babel-eslint",
  
    env: {
      es6: true
    },
  
    plugins: [
      "eslint-comments",
      "flowtype",
      "prettier",
      "react",
      "react-hooks",
      "react-native",
      "jest"
    ],
  
    // Map from global var to bool specifying if it can be redefined
    globals: {
      __DEV__: true,
      __dirname: false,
      __fbBatchedBridgeConfig: false,
      alert: false,
      cancelAnimationFrame: false,
      cancelIdleCallback: false,
      clearImmediate: true,
      clearInterval: false,
      clearTimeout: false,
      console: false,
      document: false,
      escape: false,
      Event: false,
      EventTarget: false,
      exports: false,
      fetch: false,
      FormData: false,
      global: false,
      Map: true,
      module: false,
      navigator: false,
      process: false,
      Promise: true,
      requestAnimationFrame: true,
      requestIdleCallback: true,
      require: false,
      Set: true,
      setImmediate: true,
      setInterval: false,
      setTimeout: false,
      window: false,
      XMLHttpRequest: false
    },
  
    rules: {
      // General
      "comma-dangle": [1, "always-multiline"], // allow or disallow trailing commas
      "no-cond-assign": 1, // disallow assignment in conditional expressions
      "no-console": 0, // disallow use of console (off by default in the node environment)
      "no-const-assign": 2, // disallow assignment to const-declared variables
      "no-constant-condition": 0, // disallow use of constant expressions in conditions
      "no-control-regex": 1, // disallow control characters in regular expressions
      "no-debugger": 1, // disallow use of debugger
      "no-dupe-class-members": 2, // Disallow duplicate name in class members
      "no-dupe-keys": 2, // disallow duplicate keys when creating object literals
      "no-empty": 0, // disallow empty statements
      "no-ex-assign": 1, // disallow assigning to the exception in a catch block
      "no-extra-boolean-cast": 1, // disallow double-negation boolean casts in a boolean context
      "no-extra-parens": 0, // disallow unnecessary parentheses (off by default)
      "no-extra-semi": 1, // disallow unnecessary semicolons
      "no-func-assign": 1, // disallow overwriting functions written as function declarations
      "no-inner-declarations": 0, // disallow function or variable declarations in nested blocks
      "no-invalid-regexp": 1, // disallow invalid regular expression strings in the RegExp constructor
      "no-negated-in-lhs": 1, // disallow negation of the left operand of an in expression
      "no-obj-calls": 1, // disallow the use of object properties of the global object (Math and JSON) as functions
      "no-regex-spaces": 1, // disallow multiple spaces in a regular expression literal
      "no-reserved-keys": 0, // disallow reserved words being used as object literal keys (off by default)
      "no-sparse-arrays": 1, // disallow sparse arrays
      "no-unreachable": 2, // disallow unreachable statements after a return, throw, continue, or break statement
      "use-isnan": 1, // disallow comparisons with the value NaN
      "valid-jsdoc": 0, // Ensure JSDoc comments are valid (off by default)
      "valid-typeof": 1, // Ensure that the results of typeof are compared against a valid string
  
      // Best Practices
      // These are rules designed to prevent you from making mistakes. They either prescribe a better way of doing something or help you avoid footguns.
  
      "block-scoped-var": 0, // treat var statements as if they were block scoped (off by default)
      complexity: 0, // specify the maximum cyclomatic complexity allowed in a program (off by default)
      "consistent-return": 0, // require return statements to either always or never specify values
      curly: 1, // specify curly brace conventions for all control statements
      "default-case": 0, // require default case in switch statements (off by default)
      "dot-notation": 1, // encourages use of dot notation whenever possible
      eqeqeq: [1, "allow-null"], // require the use of === and !==
      "guard-for-in": 0, // make sure for-in loops have an if statement (off by default)
      "no-alert": 1, // disallow the use of alert, confirm, and prompt
      "no-caller": 1, // disallow use of arguments.caller or arguments.callee
      "no-div-regex": 1, // disallow division operators explicitly at beginning of regular expression (off by default)
      "no-else-return": 0, // disallow else after a return in an if (off by default)
      "no-eq-null": 0, // disallow comparisons to null without a type-checking operator (off by default)
      "no-eval": 2, // disallow use of eval()
      "no-extend-native": 1, // disallow adding to native types
      "no-extra-bind": 1, // disallow unnecessary function binding
      "no-fallthrough": 1, // disallow fallthrough of case statements
      "no-floating-decimal": 1, // disallow the use of leading or trailing decimal points in numeric literals (off by default)
      "no-implied-eval": 1, // disallow use of eval()-like methods
      "no-labels": 1, // disallow use of labeled statements
      "no-iterator": 1, // disallow usage of __iterator__ property
      "no-lone-blocks": 1, // disallow unnecessary nested blocks
      "no-loop-func": 0, // disallow creation of functions within loops
      "no-multi-str": 0, // disallow use of multiline strings
      "no-native-reassign": 0, // disallow reassignments of native objects
      "no-new": 1, // disallow use of new operator when not part of the assignment or comparison
      "no-new-func": 2, // disallow use of new operator for Function object
      "no-new-wrappers": 1, // disallows creating new instances of String,Number, and Boolean
      "no-octal": 1, // disallow use of octal literals
      "no-octal-escape": 1, // disallow use of octal escape sequences in string literals, such as var foo = "Copyright \251";
      "no-proto": 1, // disallow usage of __proto__ property
      "no-redeclare": 0, // disallow declaring the same variable more then once
      "no-return-assign": 1, // disallow use of assignment in return statement
      "no-script-url": 1, // disallow use of javascript: urls.
      "no-self-compare": 1, // disallow comparisons where both sides are exactly the same (off by default)
      "no-sequences": 1, // disallow use of comma operator
      "no-unused-expressions": 0, // disallow usage of expressions in statement position
      "no-void": 1, // disallow use of void operator (off by default)
      "no-warning-comments": 0, // disallow usage of configurable warning terms in comments": 1,                        // e.g. TODO or FIXME (off by default)
      "no-with": 1, // disallow use of the with statement
      radix: 1, // require use of the second argument for parseInt() (off by default)
      "semi-spacing": 1, // require a space after a semi-colon
      "vars-on-top": 0, // requires to declare all vars on top of their containing scope (off by default)
      "wrap-iife": 0, // require immediate function invocation to be wrapped in parentheses (off by default)
      yoda: 1, // require or disallow Yoda conditions
  
      // Variables
      // These rules have to do with variable declarations.
  
      "no-catch-shadow": 1, // disallow the catch clause parameter name being the same as a variable in the outer scope (off by default in the node environment)
      "no-delete-var": 1, // disallow deletion of variables
      "no-label-var": 1, // disallow labels that share a name with a variable
      "no-shadow": 1, // disallow declaration of variables already declared in the outer scope
      "no-shadow-restricted-names": 1, // disallow shadowing of names such as arguments
      "no-undef": 2, // disallow use of undeclared variables unless mentioned in a /*global */ block
      "no-undefined": 0, // disallow use of undefined variable (off by default)
      "no-undef-init": 1, // disallow use of undefined when initializing variables
      "no-unused-vars": [
        1,
        { vars: "all", args: "none", ignoreRestSiblings: true }
      ], // disallow declaration of variables that are not used in the code
      "no-use-before-define": 0, // disallow use of variables before they are defined
  
      // Node.js
      // These rules are specific to JavaScript running on Node.js.
  
      "handle-callback-err": 1, // enforces error handling in callbacks (off by default) (on by default in the node environment)
      "no-mixed-requires": 1, // disallow mixing regular variable and require declarations (off by default) (on by default in the node environment)
      "no-new-require": 1, // disallow use of new operator with the require function (off by default) (on by default in the node environment)
      "no-path-concat": 1, // disallow string concatenation with __dirname and __filename (off by default) (on by default in the node environment)
      "no-process-exit": 0, // disallow process.exit() (on by default in the node environment)
      "no-restricted-modules": 1, // restrict usage of specified node modules (off by default)
      "no-sync": 0, // disallow use of synchronous methods (off by default)
  
      // ESLint Comments Plugin
      // The following rules are made available via `eslint-plugin-eslint-comments`
      "eslint-comments/no-aggregating-enable": 1, // disallows eslint-enable comments for multiple eslint-disable comments
      "eslint-comments/no-unlimited-disable": 1, // disallows eslint-disable comments without rule names
      "eslint-comments/no-unused-disable": 1, // disallow disables that don't cover any errors
      "eslint-comments/no-unused-enable": 1, // // disallow enables that don't enable anything or enable rules that weren't disabled
  
      // Flow Plugin
      // The following rules are made available via `eslint-plugin-flowtype`
      "flowtype/define-flow-type": 1,
      "flowtype/use-flow-type": 1,
  
      // Prettier Plugin
      // https://github.com/prettier/eslint-plugin-prettier
      "prettier/prettier": [2],
  
      // Stylistic Issues
      // These rules are purely matters of style and are quite subjective.
  
      "key-spacing": 0,
      "keyword-spacing": 1, // enforce spacing before and after keywords
      "jsx-quotes": [1, "prefer-double"], // enforces the usage of double quotes for all JSX attribute values which doesn’t contain a double quote
      "comma-spacing": 0,
      "no-multi-spaces": 0,
      "brace-style": 0, // enforce one true brace style (off by default)
      camelcase: 0, // require camel case names
      "consistent-this": 1, // enforces consistent naming when capturing the current execution context (off by default)
      "eol-last": 1, // enforce newline at the end of file, with no multiple empty lines
      "func-names": 0, // require function expressions to have a name (off by default)
      "func-style": 0, // enforces use of function declarations or expressions (off by default)
      "new-cap": 0, // require a capital letter for constructors
      "new-parens": 1, // disallow the omission of parentheses when invoking a constructor with no arguments
      "no-nested-ternary": 0, // disallow nested ternary expressions (off by default)
      "no-array-constructor": 1, // disallow use of the Array constructor
      "no-empty-character-class": 1, // disallow the use of empty character classes in regular expressions
      "no-lonely-if": 0, // disallow if as the only statement in an else block (off by default)
      "no-new-object": 1, // disallow use of the Object constructor
      "no-spaced-func": 1, // disallow space between function identifier and application
      "no-ternary": 0, // disallow the use of ternary operators (off by default)
      "no-trailing-spaces": 1, // disallow trailing whitespace at the end of lines
      "no-underscore-dangle": 0, // disallow dangling underscores in identifiers
      "no-mixed-spaces-and-tabs": 1, // disallow mixed spaces and tabs for indentation
      quotes: [1, "single", "avoid-escape"], // specify whether double or single quotes should be used
      "quote-props": 0, // require quotes around object literal property names (off by default)
      semi: 1, // require or disallow use of semicolons instead of ASI
      "sort-vars": 0, // sort variables within the same declaration block (off by default)
      "space-in-brackets": 0, // require or disallow spaces inside brackets (off by default)
      "space-in-parens": 0, // require or disallow spaces inside parentheses (off by default)
      "space-infix-ops": 1, // require spaces around operators
      "space-unary-ops": [1, { words: true, nonwords: false }], // require or disallow spaces before/after unary operators (words on by default, nonwords off by default)
      "max-nested-callbacks": 0, // specify the maximum depth callbacks can be nested (off by default)
      "one-var": 0, // allow just one var statement per function (off by default)
      "wrap-regex": 0, // require regex literals to be wrapped in parentheses (off by default)
  
      // Legacy
      // The following rules are included for compatibility with JSHint and JSLint. While the names of the rules may not match up with the JSHint/JSLint counterpart, the functionality is the same.
  
      "max-depth": 0, // specify the maximum depth that blocks can be nested (off by default)
      "max-len": 0, // specify the maximum length of a line in your program (off by default)
      "max-params": 0, // limits the number of parameters that can be used in the function declaration. (off by default)
      "max-statements": 0, // specify the maximum number of statement allowed in a function (off by default)
      "no-bitwise": 1, // disallow use of bitwise operators (off by default)
      "no-plusplus": 0, // disallow use of unary operators, ++ and -- (off by default)
  
      // React Plugin
      // The following rules are made available via `eslint-plugin-react`.
  
      "react/display-name": 0,
      "react/jsx-boolean-value": 0,
      "react/jsx-no-comment-textnodes": 1,
      "react/jsx-no-duplicate-props": 2,
      "react/jsx-no-undef": 2,
      "react/jsx-sort-props": 0,
      "react/jsx-uses-react": 1,
      "react/jsx-uses-vars": 1,
      "react/no-did-mount-set-state": 1,
      "react/no-did-update-set-state": 1,
      "react/no-multi-comp": 0,
      "react/no-string-refs": 1,
      "react/no-unknown-property": 0,
      "react/prop-types": 0,
      "react/react-in-jsx-scope": 1,
      "react/self-closing-comp": 1,
      "react/wrap-multilines": 0,
  
      // React-Hooks Plugin
      // The following rules are made available via `eslint-plugin-react-hooks`
      "react-hooks/rules-of-hooks": "error",
  
      // React-Native Plugin
      // The following rules are made available via `eslint-plugin-react-native`
  
      "react-native/no-inline-styles": 1,
  
      // Jest Plugin
      // The following rules are made available via `eslint-plugin-jest`.
      "jest/no-disabled-tests": 1,
      "jest/no-focused-tests": 1,
      "jest/no-identical-title": 1,
      "jest/valid-expect": 1
    },
  
    overrides: [
      {
        files: [
          "**/__fixtures__/**/*.js",
          "**/__mocks__/**/*.js",
          "**/__tests__/**/*.js",
          "jest/**/*.js",
          "RNTester/**/*.js"
        ],
        globals: {
          // Expose some Jest globals for test helpers
          afterAll: true,
          afterEach: true,
          beforeAll: true,
          beforeEach: true,
          expect: true,
          jest: true
        }
      },
      {
        files: ["**/__tests__/**/*-test.js"],
        env: {
          jasmine: true,
          jest: true
        }
      }
    ],
  
    settings: {
      react: {
        version: "detect"
      }
    }
  };