/check-bun

Audit project for Bun compatibility. Output findings as structured report.

What This Does

• Check current package manager setup

• Identify compatibility blockers

• Assess migration opportunities

• Output prioritized findings (P0-P3)

This is a primitive. It only investigates and reports. Use /fix-bun to fix issues or /bun for full migration.

Process

1. Current State Assessment

What package manager is in use?

[ -f "pnpm-lock.yaml" ] && echo "Current: pnpm" [ -f "bun.lock" ] || [ -f "bun.lockb" ] && echo "Current: bun" [ -f "package-lock.json" ] && echo "Current: npm" [ -f "yarn.lock" ] && echo "Current: yarn"

Check packageManager field

grep -o '"packageManager":.*' package.json 2>/dev/null || echo "No packageManager field"

Multiple lockfiles?

ls -la .lock 2>/dev/null | wc -l

2. Deployment Target Check

Vercel?

[ -f "vercel.json" ] && echo "Vercel deployment detected"

Expo/EAS?

[ -f "app.json" ] && grep -q "expo" app.json && echo "Expo detected - Bun NOT supported"

Netlify?

[ -f "netlify.toml" ] && echo "Netlify deployment - limited Bun support"

Fly.io?

[ -f "fly.toml" ] && echo "Fly.io deployment - full Bun support"

3. Dependency Compatibility Check

Native modules that may have issues

grep -E "sharp|bcrypt|canvas|puppeteer|better-sqlite3" package.json 2>/dev/null

Check for known problematic packages

grep -E "node-gyp|node-pre-gyp" package-lock.json pnpm-lock.yaml 2>/dev/null | head -5

4. CI Configuration Check

GitHub Actions using pnpm?

grep -l "pnpm/action-setup" .github/workflows/*.yml 2>/dev/null

Should be using oven-sh/setup-bun?

grep -l "oven-sh/setup-bun" .github/workflows/*.yml 2>/dev/null

5. Workspace Configuration Check

pnpm workspace file exists?

[ -f "pnpm-workspace.yaml" ] && echo "pnpm-workspace.yaml found"

Workspaces in package.json?

grep -q '"workspaces"' package.json && echo "workspaces field in package.json"

6. Node.js API Usage Check

Heavy Node.js API usage that may differ in Bun

grep -rE "child_process|cluster|vm|dgram" --include=".ts" --include=".js" src/ 2>/dev/null | head -10

Worker threads

grep -rE "worker_threads" --include=".ts" --include=".js" src/ 2>/dev/null | head -5

Output Format

Bun Compatibility Audit

P0: Blockers (Cannot migrate)

• Expo/EAS detected - Bun runtime not supported by EAS Build
• Native module canvas may not work with Bun

P1: Essential (Must fix before migration)

• Mixed lockfiles: both pnpm-lock.yaml and bun.lock present
• CI using pnpm/action-setup, needs oven-sh/setup-bun
• pnpm-workspace.yaml needs migration to package.json workspaces

P2: Important (Should address)

• Scripts using node instead of bun for execution
• Test runner is Jest, consider Bun test runner
• No frozen-lockfile in CI

P3: Nice to Have (Optimization opportunities)

• Could use Bun's native SQLite instead of better-sqlite3
• Build scripts could use Bun shell

Summary

• Current: pnpm
• Deployment: Vercel (partial Bun support)
• Blockers: 0
• Migration complexity: LOW/MEDIUM/HIGH
• Recommendation: [PROCEED/HYBRID/SKIP]

Priority Mapping

Finding Priority

Expo/EAS deployment P0 (blocker)

Native modules incompatible P0 (blocker)

Mixed lockfiles P1

CI not updated P1

Workspace config needs migration P1

Scripts using node

P2

Test runner not optimized P2

Missed optimization opportunities P3

Migration Complexity Assessment

LOW: No blockers, simple dependencies, flexible deployment

• Few/no native modules

• Deployment platform supports Bun

• No pnpm-specific features used

MEDIUM: Some work required, compatible target

• Native modules that work with Bun

• CI needs updating

• Workspace config needs migration

HIGH: Significant challenges or partial adoption

• Platform limitations (Vercel serverless, etc.)

• Heavy native module usage

• Complex monorepo setup

Recommendation Matrix

Blockers Deployment Complexity Recommendation

0 Supports Bun LOW PROCEED

0 Supports Bun MEDIUM PROCEED with care

0 Partial support Any HYBRID setup

Any Any HIGH SKIP or HYBRID

0 Doesn't support Any SKIP

Related

• /fix-bun

• Fix Bun migration issues one at a time

• /bun

• Full Bun migration orchestrator

• /bun-best-practices

• When to use Bun (reference)