@foxglove/eslint-plugin/configs/typescript.js

Foxglove ESLint rules and configuration

// @ts-expect-error Missing type definitions
const importPlugin = require("eslint-plugin-import");
const tseslint = require("typescript-eslint");

/** @type {import("eslint").Linter.Config[]} */
module.exports = [
  ...tseslint.configs.strictTypeChecked,
  ...tseslint.configs.stylisticTypeChecked,
  {
    plugins: {
      import: importPlugin,
    },
  },
  importPlugin.configs.typescript,
  {
    rules: {
      "@typescript-eslint/no-meaningless-void-operator": [
        "error",
        { checkNever: true },
      ],
      "@foxglove/no-boolean-parameters": "error",

      // `<T>x` style assertions are not compatible with JSX code,
      // so for consistency we prefer `x as T` everywhere.
      "@typescript-eslint/consistent-type-assertions": [
        "error",
        {
          assertionStyle: "as",
        },
      ],

      "@typescript-eslint/explicit-module-boundary-types": "error",
      "@typescript-eslint/no-confusing-non-null-assertion": "error",
      "@typescript-eslint/no-explicit-any": "error",
      "@typescript-eslint/no-floating-promises": "error",
      "@typescript-eslint/no-shadow": "error",
      "@typescript-eslint/no-unnecessary-boolean-literal-compare": "error",

      "no-unused-expressions": "off",
      "@typescript-eslint/no-unused-expressions": [
        "error",
        { enforceForJSX: true },
      ],

      // The ! assertion may be used sparingly in cases where tsc cannot automatically do bounds
      // checking such as indexed array iteration
      "@typescript-eslint/no-non-null-assertion": "off",

      // unused vars must have `_` prefix
      "@typescript-eslint/no-unused-vars": [
        "error",
        {
          vars: "all",
          args: "after-used",
          varsIgnorePattern: "^_",
          argsIgnorePattern: "^_",
        },
      ],

      "@typescript-eslint/prefer-includes": "error",
      "@typescript-eslint/promise-function-async": "error",

      // Async functions without await are used to satisfy interface requirements
      "@typescript-eslint/require-await": "off",

      "@typescript-eslint/restrict-template-expressions": [
        "error",
        // Based on the strictTypeChecked defaults, but with allowNumber: true
        {
          allowAny: false,
          allowBoolean: false,
          allowNullish: false,
          allowNumber: true,
          allowRegExp: false,
          allowNever: false,
        },
      ],

      "@typescript-eslint/return-await": ["error", "always"],

      // require all cases to be checked in switch statements
      "@typescript-eslint/switch-exhaustiveness-check": "error",

      // require strict boolean comparisons for all types, except allow
      // nullable string conditionals to avoid verbose "empty or undefined" checks
      "@typescript-eslint/strict-boolean-expressions": [
        "error",
        {
          allowString: true,
          allowNullableString: true,
          allowNumber: false,
          allowNullableNumber: false,
          allowNullableBoolean: false,
          allowNullableObject: true,
          allowAny: false,
        },
      ],

      "@typescript-eslint/prefer-nullish-coalescing": [
        "error",
        { ignoreConditionalTests: true },
      ],

      // We find the following rules from the strict/stylistic configs to be overly pedantic and not
      // so useful
      "@typescript-eslint/consistent-type-definitions": "off",
      "@typescript-eslint/consistent-indexed-object-style": "off",
      "@typescript-eslint/no-dynamic-delete": "off",
      "@typescript-eslint/dot-notation": "off",
      "@typescript-eslint/array-type": "off",
      "@typescript-eslint/no-invalid-void-type": "off",
      "@typescript-eslint/unified-signatures": "off",
    },
  },
];