.eslintrc.js

// eslint-disable-next-line no-undef
module.exports = {
  env: {
    es2021: true,
    node: true,
    browser: true,
  },
  extends: "eslint:recommended",
  overrides: [],
  parserOptions: {
    ecmaVersion: "latest",
    sourceType: "module",
  },
  globals: {
    Blockly: "readonly",
    Scratch: "readonly",
  },
  rules: {
    // Unused variables commonly indicate logic errors
    "no-unused-vars": [
      "error",
      {
        // Unused arguments are useful, eg. it can be nice for blocks to accept `args` even if they don't use it
        args: "none",
        // Allow silently eating try { } catch { }
        caughtErrors: "none",
        // Variables starting with _ are intentionally unused
        argsIgnorePattern: "^_",
        varsIgnorePattern: "^_",
      },
    ],
    // Allow while (true) { }
    "no-constant-condition": [
      "error",
      {
        checkLoops: false,
      },
    ],
    // Allow empty catch {} blocks
    "no-empty": [
      "error",
      {
        allowEmptyCatch: true,
      },
    ],
    // Returning a value from a constructor() implies a mistake
    "no-constructor-return": "error",
    // new Promise(async () => {}) implies a mistake
    "no-async-promise-executor": "warn",
    // x === x implies a mistake
    "no-self-compare": "error",
    // Using ${...} in a non-template-string implies a mistake
    "no-template-curly-in-string": "error",
    // Loops that only iterate once imply a mistake
    "no-unreachable-loop": "error",
    // Detect some untrusted code execution
    "no-eval": "error",
    "no-implied-eval": "error",
    "no-new-func": "error",
    "no-script-url": "error",
    // Combinations of || and && are unreadable and may not do what you expect
    "no-mixed-operators": [
      "error",
      {
        groups: [["&&", "||"]],
      },
    ],
    // Disallow async functions that don't need to be. This is important as a Promise and non-Promise return value
    // significantly impacts the behavior of projects.
    "require-await": "error",
  },
};