Setup Lefthook

Setup Lefthook Git Hooks

Prerequisites

• Biome must be installed (biome.json should exist)
• TypeScript must be configured (tsconfig.json should exist)
• Git repository must be initialized

Installation Steps

First, verify prerequisites exist:

# Check for biome.json and tsconfig.json
ls biome.json tsconfig.json

1. Install lefthook as dev dependency:

bun add -d lefthook

2. Create .lefthook.yml configuration:

Ask the user: "Do you want the basic configuration (just linting and type checking) or the full configuration (includes Vercel & Sanity deployment)?"

Then create the appropriate configuration:

Basic Configuration (Recommended for most projects)

pre-commit:
  parallel: true
  commands:
    lint:
      run: bunx biome check --write --staged --unsafe || (echo "No files to lint" && exit 0)
    types:
      run: bunx tsc --noEmit

pre-push:
  commands:
    check-types:
      run: bunx tsc --noEmit
    lint-ci:
      run: bunx biome ci . --max-diagnostics=100 --files-ignore-unknown=true

Full Configuration (Includes Vercel & Sanity deployment)

Only use if project has Vercel and Sanity configured:

pre-commit:
  parallel: true
  commands:
    lint:
      run: bunx biome check --write --staged --unsafe || (echo "No files to lint" && exit 0)
    types:
      run: bunx tsc --noEmit

pre-push:
  commands:
    check-types:
      run: bunx tsc --noEmit
    lint-ci:
      run: bunx biome ci . --max-diagnostics=100 --files-ignore-unknown=true
    build-deploy:
      interactive: true
      run: vercel build --prod && vercel deploy --prebuilt --prod --archive=tgz && bunx sanity deploy

3. Install git hooks:

bunx lefthook install

What This Configures

Pre-commit (runs in parallel):

• Lint: Auto-fixes staged files with Biome
• Types: Validates TypeScript types

Pre-push (Basic):

• Check types: Full TypeScript validation
• Lint CI: Biome CI check with diagnostics

Pre-push (Full - optional):

• Build & Deploy: Interactive Vercel and Sanity deployment

Verification

Test the hooks:

# Test pre-commit hook
echo "// test" >> app/page.tsx
git add app/page.tsx
git commit -m "test commit"

# Should run biome check and tsc

Notes

• Hooks run automatically on git commit/push
• Pre-commit runs only on staged files
• Build-deploy hook is interactive and requires user confirmation