Bun Workspace Optimizer#

Analyze and optimize Bun workspace configurations for monorepos. Audit dependency hoisting, script performance, build pipelines, and workspace settings. Use when setting up Bun workspaces, migrating from npm/yarn/pnpm workspaces, or optimizing monorepo build times.

Usage#

text

"Optimize my Bun workspace setup"
"Analyze dependencies across my monorepo packages"
"Find duplicate dependencies in my workspace"
"Speed up my monorepo builds with Bun"
"Migrate my pnpm workspace to Bun"

How It Works#

1. Workspace Discovery#

Map the monorepo structure:

bash

# Check Bun version and workspace config
bun --version
cat package.json | python3 -c "
import json, sys
d = json.load(sys.stdin)
ws = d.get('workspaces', [])
if isinstance(ws, dict): ws = ws.get('packages', [])
for w in ws: print(f'  {w}')
"

# Find all package.json files
find . -name "package.json" -not -path "*/node_modules/*" -maxdepth 3

2. Dependency Analysis#

• Hoisting audit: Which deps are properly hoisted to root?
• Version conflicts: Same package with different versions across packages
• Duplicate installs: Packages installed in multiple workspaces unnecessarily
• Phantom dependencies: Used but not declared in package.json
• Circular dependencies: Workspace packages depending on each other in cycles
• Unused dependencies: Declared but never imported

bash

# Check for version mismatches
find . -name "package.json" -not -path "*/node_modules/*" -maxdepth 3 -exec python3 -c "
import json, sys, os
from collections import defaultdict
versions = defaultdict(set)
for f in sys.argv[1:]:
    try:
        d = json.load(open(f))
        pkg = d.get('name', f)
        for deps in [d.get('dependencies',{}), d.get('devDependencies',{})]:
            for k,v in deps.items():
                versions[k].add((v, pkg))
    except: pass
for pkg, vs in sorted(versions.items()):
    unique = set(v for v,_ in vs)
    if len(unique) > 1:
        print(f'⚠️  {pkg}: {dict((src,ver) for ver,src in vs)}')
" {} +

3. Build Pipeline Optimization#

• Script analysis: Which scripts can run in parallel?
• Bun build vs bundlers: Where can bun build replace webpack/esbuild/rollup?
• TypeScript compilation: Using Bun's built-in TS support vs tsc?
• Test runner: Migrating to bun test from Jest/Vitest?
• Cache utilization: Are builds leveraging Bun's module cache?

4. Performance Profiling#

Compare key operations:

• bun install time vs npm/yarn/pnpm
• bun run script startup overhead
• bun build vs alternative bundlers
• bun test vs existing test runner
• Cold start vs warm start times

5. Configuration Best Practices#

Check bunfig.toml and workspace config:

• Install settings: frozen-lockfile for CI
• Registry configuration for private packages
• Scoped package settings
• Telemetry and logging preferences
• Module resolution settings

6. Migration Guide#

For teams migrating from other package managers:

• From npm: Remove package-lock.json, run bun install
• From yarn: Handle .yarnrc.yml settings, yarn plugins
• From pnpm: Convert pnpm-workspace.yaml to package.json workspaces
• CI updates: Replace npm/yarn commands in CI config
• Docker: Use oven/bun base image

Output#

text

## Bun Workspace Analysis

**Packages:** 12 | **Total deps:** 847 | **Hoisted:** 91%

### 🔴 Issues (2)
1. Circular dependency: packages/core → packages/utils → packages/core
   → Extract shared types into packages/types
2. 3 packages pin react@18.2, root has react@18.3 → version conflict
   → Align all to ^18.3.0 and hoist to root

### 🟡 Optimizations (4)
3. packages/web still uses webpack — switch to `bun build`
   → Estimated build time: 12s → 0.8s
4. 23 duplicate devDependencies across packages
   → Move to root devDependencies, save 45MB node_modules
5. `bun test` would replace Jest + ts-jest setup (3 packages)
   → Remove 12 jest config files, gain native TS support
6. Missing `bunfig.toml` — no frozen lockfile in CI
   → Add [install] frozen-lockfile = true

### 📊 Performance Comparison
| Operation | Current | With Bun | Speedup |
|-----------|---------|----------|---------|
| Install   | 34s     | 2.1s     | 16x     |
| Build     | 18s     | 1.2s     | 15x     |
| Tests     | 45s     | 12s      | 3.7x    |
| CI Total  | 4m 12s  | 1m 05s   | 3.8x    |

### ✅ Good Practices
- Clean workspace boundaries
- Shared tsconfig via extends
- Root scripts properly delegate to workspace packages