.eslintrc.json

{
  "env": {
    "node": true, // this is the best starting point
    "browser": true, // for react web
    "es6": true, // enables es6 features
    "jest": true // unit testing
  },
  "parser": "babel-eslint", // needed to make babel stuff work properly
  "extends": "airbnb",
  "rules": {
    "react/jsx-filename-extension": [1, { "extensions": [".js", ".jsx"] }],
    "import/no-named-as-default": 0,
    "function-paren-newline": ["error", "consistent"],
    "no-console": "off", // console logging is extremely useful
    "no-mixed-operators": "off", // I personally don't see anything wrong with x + y / z
    "prefer-rest-params": "off",
    "no-underscore-dangle": "off", // firebase loves returning props with leading underscores
    "prefer-destructuring": [
      "error",
      {
        "array": false,
        "object": true
      }
    ],
    "react/require-default-props": "off",
    "arrow-body-style": 0, // don't enforce arrow-body-style, block body (() => { ... }) and single expression (() => ...) depends on use case
    "object-curly-newline": "off",
    "react/no-did-update-set-state": "off", // sometimes this is necessary
    "arrow-parens": "off", // parenthesis around single argument or not, depends on the use case
    "no-bitwise": "off",
    "no-nested-ternary": "off", // I personally prefer nested ternaries
    "react/jsx-indent": "off", // conflicts with prettier
    "import/no-extraneous-dependencies": "off", // for this project, we don't want to add dependencies where not necessary
    "react/sort-comp": [
      1,
      { "order": ["constructor", "static-methods", "lifecycle", "everything-else", "render"] }
    ]
  },
  "plugins": ["react", "react-native"],
  "globals": {
    "__DEV__": true
  },
  "settings": {
    "import/resolver": {
      "node": {
        "extensions": [".js", ".android.js", ".ios.js"]
      }
    }
  }
}