.eslintrc.json

{
  "env": {
    "browser": true,
    "es6": true
  },
  "extends": "react-app",
  "parserOptions": {
    "ecmaFeatures": {
      "experimentalObjectRestSpread": true,
      "jsx": true
    }
  },
  "plugins": [
    "react",
    "chai-friendly"
  ],
  "rules": {
    "linebreak-style": ["error", "unix"],
    "semi": ["error", "always"],
    "react/jsx-uses-react": "error",
    "react/jsx-uses-vars": "error",
    "react/react-in-jsx-scope": "error",
    "no-console": [
      "error",
      {
        "allow": ["warn", "error"]
      }
    ],

    // Chai shortcut syntax expect(...).to.be.null triggers default eslint validation
    // This plugin overrides it for just chai expressions.
    // https://www.npmjs.com/package/eslint-plugin-chai-friendly
    "no-unused-expressions": 0,
    "chai-friendly/no-unused-expressions": 2,

    // Import sorting does not take into account react vs mabl libraries. Turned off for now.
    "sort-imports": ["off", {
      "ignoreCase": false,
      "ignoreDeclarationSort": false,
      "ignoreMemberSort": false,
      "memberSyntaxSortOrder": ["none", "all", "multiple", "single"]
    }],

    // Additions from airbnb code style, set to warn for now
    // es6

    // require let or const instead of var
    "no-var": "warn",

    // suggest using of const declaration for variables that are never modified after declared
    "prefer-const": ["warn"],

    // Prefer destructuring from arrays and objects
    // https://eslint.org/docs/rules/prefer-destructuring
    "prefer-destructuring": ["warn", {
      "VariableDeclarator": {
        "array": false,
        "object": true
      },
      "AssignmentExpression": {
        "array": true,
        "object": true
      }
    }, {
      "enforceForRenamedProperties": false
    }],

    // Enforce props alphabetical sorting
    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-sort-props.md
    "react/jsx-sort-props": ["warn", {
      "ignoreCase": true,
      "callbacksLast": false,
      "shorthandFirst": false,
      "shorthandLast": false,
      "noSortAlphabetically": false,
      "reservedFirst": false
    }],

    // Prevent unused propType definitions
    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-unused-prop-types.md
    "react/no-unused-prop-types": ["warn", {
      "customValidators": [
      ],
      "skipShapeProps": true
    }],

    // Prevent missing props validation in a React component definition
    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prop-types.md
    "react/prop-types": ["warn", {
      "ignore": [],
      "customValidators": [],
      "skipUndeclared": false
    }],

    // Enforce propTypes declarations alphabetical sorting
    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/sort-prop-types.md
    "react/sort-prop-types": ["warn", {
      "ignoreCase": true,
      "callbacksLast": false,
      "requiredFirst": false,
      "sortShapeProp": true
    }],


    // Require style prop value be an object or var
    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/style-prop-object.md
    "react/style-prop-object": "warn",

    // react
    // Enforce all defaultProps have a corresponding non-required PropType
    // https://github.com/yannickcr/eslint-plugin-react/blob/9e13ae2c51e44872b45cc15bf1ac3a72105bdd0e/docs/rules/default-props-match-prop-types.md
    "react/default-props-match-prop-types": ["warn", { "allowRequiredDefaults": false }],

    // variables

    // disallow declaration of variables that are not used in the code
    "no-unused-vars": ["warn", { "vars": "all", "args": "after-used", "ignoreRestSiblings": true }],

    // disallow use of variables before they are defined
    "no-use-before-define": ["warn", { "functions": false, "classes": true, "variables": true }]
  }
}