Bun Package Manager : Le Runtime JavaScript le Plus Rapide en 2026

Bun est un runtime JavaScript tout-en-un écrit en Zig. Son gestionnaire de paquets installe les dépendances jusqu'à 23x plus vite que npm.

Installation et commandes de base

Bun s'installe en quelques secondes et fonctionne comme un remplacement direct aux commandes npm.

# Install Bun
curl -fsSL https://bun.sh/install | bash

# Verify installation
bun --version  # 1.x.x

# Install dependencies (reads package.json)
bun install

# Install a specific package
bun add express
bun add -d typescript @types/node   # dev dependency
bun add -g bunx                     # global install

# Remove a package
bun remove lodash

# Update all packages
bun update

# Run a script from package.json
bun run build
bun run dev

# Execute a TypeScript file directly (no transpile step)
bun run index.ts

Workspaces (support monorepo)

Bun supporte les workspaces de style npm pour les monorepos.

// package.json — monorepo root
{
  "name": "my-monorepo",
  "workspaces": [
    "packages/*",
    "apps/*"
  ],
  "scripts": {
    "dev": "bun run --filter '*' dev",
    "build": "bun run --filter '*' build",
    "test": "bun test"
  }
}

// Run a script only in specific workspace
bun run --filter @myapp/web dev

// Install a dependency in a specific workspace
bun add react --cwd apps/web

// Link a local workspace package
// (Bun automatically resolves workspace: protocol)

Le fichier de verrouillage binaire (bun.lockb)

Bun utilise un fichier de verrouillage binaire au lieu de JSON.

# bun.lockb is a binary lockfile (much faster to parse than JSON)
# To view lockfile contents in human-readable form:
bun bun.lockb  # prints as yarn.lock format

# To regenerate lockfile:
bun install --frozen-lockfile  # CI: fails if lockfile is stale

# Migrating from npm/yarn/pnpm:
# Bun reads package-lock.json, yarn.lock, pnpm-lock.yaml
# to preserve existing versions on first install

# .gitignore for Bun:
# node_modules/
# *.lock  (optional — commit bun.lockb for reproducible installs)

Benchmarks de performance

Le gestionnaire de paquets de Bun est nettement plus rapide que toutes les alternatives.

# Benchmark: installing react + 1400 packages
# (warm cache, MacBook M2 Pro)

npm install:   28.3s
yarn install:  14.1s
pnpm install:   9.4s
bun install:    1.2s   # 23x faster than npm!

# Cold cache (first install, no node_modules)
npm install:   38.7s
bun install:    4.1s   # 9x faster

# bun install uses:
# - Symlink-based node_modules (like pnpm)
# - Binary lockfile (bun.lockb) for fast parsing
# - Parallel downloads
# - Global package cache (~/.bun/install/cache)
# - Native code (written in Zig)

bunx et outils intégrés

bunx exécute des paquets sans téléchargement en utilisant des binaires en cache.

# bunx — like npx but instant (no download delay)
bunx create-next-app@latest my-app
bunx prettier --write .
bunx eslint src/

# Run TypeScript directly
bun index.ts            # works without ts-node or compilation
bun --watch server.ts   # auto-restart on file changes

# Bun's built-in test runner (Jest-compatible API)
bun test
bun test --watch
bun test src/utils.test.ts

// Example test file
import { expect, test, describe } from 'bun:test';

describe('math', () => {
    test('adds numbers', () => {
        expect(1 + 2).toBe(3);
    });

    test('async operations', async () => {
        const result = await fetch('https://api.example.com/data');
        expect(result.ok).toBe(true);
    });
});

Scripts et intégration build

Bun exécute les scripts package.json plus vite que npm/yarn.

// package.json scripts with Bun
{
  "scripts": {
    "dev": "bun --watch src/index.ts",
    "build": "bun build src/index.ts --outdir dist --target node",
    "bundle:web": "bun build src/app.ts --outdir public/js --target browser --minify",
    "test": "bun test",
    "lint": "bunx eslint src/",
    "format": "bunx prettier --write src/"
  }
}

// Bun's built-in bundler (replaces esbuild/webpack for simple cases)
// bun build src/index.ts --outdir dist --target node --minify

// Environment variables (Bun auto-loads .env files)
// No need for dotenv package!
console.log(process.env.DATABASE_URL); // works in Bun automatically

Bun vs npm vs pnpm vs Yarn

Bonnes pratiques

• Committer bun.lockb pour des installations reproductibles.
• Utiliser bun --watch pour le développement.
• Migrer progressivement depuis npm.
• Pour les monorepos, combiner Bun workspaces avec Turborepo.
• Bun charge automatiquement .env — pas besoin de dotenv.

Foire aux questions