Node on Commentary of Takao

Node.js Stable Support for Requiring ESM Modules

Wed, 05 Nov 2025 00:00:00 +0900

Node.js Stable Support for Requiring ESM Modules

For years, Node.js developers faced a painful divide: CommonJS (CJS) and ES Modules (ESM) coexisted with limited interoperability. CJS code could import() ESM modules asynchronously, but require() — the synchronous loading mechanism at the heart of CJS — could not load ESM at all. This forced codebase migrations to be all-or-nothing affairs.

That changed with Node.js 22 and 23, which stabilized the --experimental-require-module flag. As of Node 23, synchronous require() can load ES modules, provided the ESM graph does not use top-level await.

ESM vs CommonJS Interop Challenges in Node.js

Fri, 25 Jul 2025 00:00:00 +0900

Introduction

Node.js has supported ECMAScript Modules (ESM) since v12, but the ecosystem remains deeply rooted in CommonJS (CJS). Mixing the two module systems in a single project — or consuming CJS packages from ESM code — introduces subtle pitfalls around exports, default imports, and globals. This article maps the interop boundary and provides concrete strategies for a smooth migration.

CJS vs ESM at a Glance

Aspect	CommonJS	ESM
File extensions	`.js`, `.cjs`	`.js`, `.mjs`
Default in `package.json`	`"type": "commonjs"`	`"type": "module"`
Loading	Synchronous (`require()`)	Asynchronous (`import`)
Top-level `this`	`module.exports`	`undefined`
`__dirname` / `__filename`	Available	Not available
Live bindings	Copy exports	Live bindings

Configuring the Module System

You control the module system via the package.json "type" field:

Comparing Package Managers: npm, pnpm, and yarn

Tue, 15 Apr 2025 00:00:00 +0900

Introduction

In JavaScript and Node.js development, package managers are essential daily tools.

While npm remains the default industry standard, modern alternatives like pnpm (famous for saving disk space and speed) and yarn (featuring zero-installs and Plug’n’Play modes) offer distinct architectures.

Although they resolve the same package.json specifications, their internal storage structures, dependency resolutions, and security features differ. This article compares these three package managers to help you choose the best tool for your next project.