.eslintrc

{
  "extends": "eslint:recommended",
  "env": {
    // Enables all ES6 features except modules.
    "es6": true
  },
  "parserOptions": {
    // Enable ES6 modules to have all language features covered.
    "sourceType": "module"
  },
  "ecmaFeatures": {
    // Enable ES6 modules to have all language features covered.
    "modules": true
  },
  "rules": {
    // Require dangling comma at the end of any  multiline list/object. This is to be consistent
    // with backend code.
    "comma-dangle": [2, "always-multiline"],
    // Disallow trailing spaces. This is to unify code because editors may have different
    // settings.
    "no-trailing-spaces": 2,
    // Disallow modifying constant variables.
    "no-const-assign": 2,
    // Force using 'let' or 'const' instead of 'var'. This is to prevent from var hoisting bugs.
    "no-var": 2,
    // Require semicolons in every place they are valid. This is to prevent from automatic
    // semicolon insertion bugs.
    "semi": [2, "always"],
    // Disallow setting strict mode in files. All JS code in the project uses ES6 modules so is
    // implicitly strict.
    "strict": [2, "never"],
    // No spacing in object literals nor in imports/exports.
    "object-curly-spacing": [2, "never"]
  }
}