Git Hooks

Git Hooks Management

Overview

This monorepo uses a fast pre-commit hook that only runs Prettier (~1-2 seconds). ESLint, typecheck, and tests run in CI.

Why? ESLint with TypeScript type-aware rules takes ~2 minutes per file due to project-wide type loading.

Quick Reference

Normal Commit (~1-2 seconds)

git commit -m "feat: add feature"

Bypass All Checks (instant)

git commit --no-verify -m "message"
# or
TEMP_COMMIT=1 git commit -m "[temp] message"

Auto-bypass Prefixes

Commits starting with these bypass the hook:

• [temp] - temporary, will squash
• [wip] - work in progress
• [skip-ci] - skip CI
• [no-verify] - explicit bypass

What Runs Where

Performance History

Original hook: ~3-5 minutes

• lint-staged (ESLint): ~2 minutes
• Turbo typecheck: ~2 minutes
• Vitest tests: ~90 seconds

Optimized hook: ~1-2 seconds

• Prettier only on staged files

Before Optimizing Your Hook

Benchmark each step to identify the bottleneck:

# Benchmark lint-staged
time npx lint-staged

# Benchmark ESLint directly on a single file
time pnpm exec eslint packages/core/src/index.ts --fix

# Benchmark Prettier directly
time pnpm exec prettier packages/core/src/index.ts --write

# Benchmark typecheck
time pnpm turbo run typecheck --filter='[HEAD]'

Performance Comparison (This Repo)

Why ESLint is Slow

The .eslintrc.js has type-aware linting enabled:

parserOptions: {
  project: './tsconfig.eslint.json',  // This loads entire TS project
}

This makes ESLint load and parse the entire TypeScript project for every file. In a monorepo with many packages, this can take 2+ minutes even for a single file.

Diagnosing Slow ESLint Rules

# Show timing for each rule
TIMING=1 pnpm exec eslint packages/core/src/index.ts

# Output shows which rules are slowest:
# Rule                          | Time (ms)
# @typescript-eslint/no-unsafe* | 45000ms  <- type-aware rules

Options to Fix

1. Remove project option - disables type-aware rules, fastest
2. Use TIMING=1 - identify and disable specific slow rules
3. Skip ESLint in pre-commit - run in CI only (current approach)
4. Switch to Biome - faster Rust-based linter

Manual Checks Before PR

Run full validation before creating PRs:

# Full CI-equivalent check
pnpm turbo run typecheck lint test

# Or individually
pnpm exec eslint .
pnpm turbo run typecheck
pnpm test

Hook Configuration

Location: .husky/pre-commit

Current hook does:

1. Get staged .ts, .tsx, .json, .md, .yml files
2. Run Prettier on them
3. Re-stage formatted files

Troubleshooting

Hook still slow?

Check if someone re-added lint-staged:

grep -n "lint-staged\|eslint" .husky/pre-commit

Need ESLint locally?

Run it manually on specific files:

pnpm exec eslint packages/core/src/myfile.ts

CI failing but local passes?

The hook doesn't run ESLint/typecheck. Run locally:

pnpm turbo run typecheck lint

Common ESLint Errors in CI

no-case-declarations: Lexical declarations (const, let, class, function) in switch case blocks must be wrapped in braces:

// ❌ Bad - ESLint error
switch (method) {
  case 'storage.get':
    const value = await db.get(key); // Error: Unexpected lexical declaration
    return res.json({ data: value });
}

// ✅ Good - wrap case block in braces
switch (method) {
  case 'storage.get': {
    const value = await db.get(key);
    return res.json({ data: value });
  }
}

This pattern is common in route handlers and bridge API implementations.