readme.md

eslint-plugin-optimal-modules

An ESLint plugin to enforce optimal JavaScript module design.

Installation

To install eslint-plugin-optimal-modules with npm, run:

npm install eslint-plugin-optimal-modules --save-dev

To use the recommended config, add the following ESLint “flat” config in eslint.config.mjs:

// @ts-check

import eslintPluginOptimalModules from "eslint-plugin-optimal-modules";

/**
 * ESLint config.
 * @satisfies {Array<import("eslint").Linter.Config>}
 */
const eslintConfig = [eslintPluginOptimalModules.configs.recommended];

export default eslintConfig;

Alternatively, manually configure the plugin and the desired rules:

// @ts-check

import eslintPluginOptimalModules from "eslint-plugin-optimal-modules";

/**
 * ESLint config.
 * @satisfies {Array<import("eslint").Linter.Config>}
 */
const eslintConfig = [
  {
    plugins: {
      "optimal-modules": eslintPluginOptimalModules,
    },
    rules: {
      "optimal-modules/no-named-exports": "error",
    },
  },
];

export default eslintConfig;

To allow named exports in Storybook story modules that have a Component Story Format (CSF):

// @ts-check

import eslintPluginOptimalModules from "eslint-plugin-optimal-modules";

/**
 * ESLint config.
 * @satisfies {Array<import("eslint").Linter.Config>}
 */
const eslintConfig = [
  eslintPluginOptimalModules.configs.recommended,
  {
    files: ["**/*.stories.{mjs,cjs,js,mts,cts,ts,tsx}"],
    rules: {
      "optimal-modules/no-named-exports": "off",
    },
  },
];

export default eslintConfig;

Rules

Rule no-named-exports

Prohibits using named exports for optimal module design.

Valid examples:

// No exports.
const a = true;

// Default export.
export default true;

// Default export.
const a = true;
export { a as default };

// TypeScript type default export.
type A = boolean;
export type { A as default };

Invalid examples:

// Named export.
export const a = true;

// Named export.
const a = true;
export { a };

// TypeScript type named export.
export type A = boolean;

To fix the above errors, move the thing being exported to its own module as a default export.

Configs

Config recommended

Enabled rules:

• no-named-exports (error).

Requirements

Supported runtime environments:

• Node.js versions ^18.18.0 || ^20.9.0 || >=21.1.0.

Projects must configure TypeScript to use types from the CommonJS modules that have a // @ts-check comment:

• compilerOptions.allowJs should be true.
• compilerOptions.maxNodeModuleJsDepth should be reasonably large, e.g. 10.
• compilerOptions.module should be "node16" or "nodenext".

Exports

These CommonJS modules are exported via the package.json field exports:

• eslintPluginOptimalModules.js