# TypeScript Checking Convention

This document describes the TypeScript checking convention established for the Webamp monorepo.

## Current Status

Each TypeScript-enabled package in the monorepo now has a consistent `type-check` script that performs type checking without emitting files.

**Progress: 5 out of 6 packages now passing! 🎉**

### Package Status

#### ✅ Passing Packages

- **webamp**: Clean TypeScript compilation
- **ani-cursor**: Clean TypeScript compilation
- **skin-database**: Clean TypeScript compilation (fixed JSZip types, Jest types, and Buffer compatibility issues)
- **webamp-docs**: Clean TypeScript compilation
- **winamp-eqf**: Clean TypeScript compilation (ES module with full type definitions)

#### ❌ Failing Packages (Need fixes)

- **webamp-modern**: 390+ TypeScript errors (conflicting type definitions, target issues)

## Convention

### Package-level Scripts

Each TypeScript package should have:

```json
{
  "scripts": {
    "type-check": "tsc --noEmit"
  }
}
```

**Important:** Always use `tsc --noEmit` to avoid accidentally creating JavaScript files in source directories.

### Root-level Script

The root package.json contains a centralized script that runs type checking for all currently passing packages:

```json
{
  "scripts": {
    "type-check": "pnpm --filter webamp type-check && pnpm --filter ani-cursor type-check && pnpm --filter skin-database type-check && pnpm --filter webamp-docs type-check && pnpm --filter winamp-eqf type-check"
  }
}
```

### CI Integration

The CI workflow (`.github/workflows/ci.yml`) runs the centralized type-check command:

```yaml
- name: Lint
  run: |
    pnpm lint
    pnpm type-check
```

## Adding New Packages

When adding a new TypeScript package to the type-check convention:

1. Add the `type-check` script to the package's `package.json`
2. Ensure the package passes type checking: `pnpm --filter <package-name> type-check`
3. Add the package to the root `type-check` script
4. Test the full suite: `pnpm type-check`

## Fixing Failing Packages

### Common Issues

1. **Missing Jest types** (Fixed in `skin-database`):

   - Install `@types/jest` and configure proper Jest setup
   - Ensure test files are properly configured

2. **Missing package types** (Fixed in `skin-database`):

   - Install missing dependencies like `jszip`, `react-redux`, `express`
   - Install corresponding `@types/` packages where needed
   - Note: Some packages like JSZip provide their own types

3. **Buffer compatibility issues** (Fixed in `skin-database`):

   - Newer TypeScript versions require explicit casting for `fs.writeFileSync`
   - Use `new Uint8Array(buffer)` instead of raw `Buffer` objects

4. **Conflicting type definitions** (`webamp-modern`):

   - Multiple versions of `@types/node` causing conflicts
   - Target configuration issues (ES5 vs ES2015+)
   - Dependency type mismatches

### Recommended Fix Strategy

1. Start with packages that have fewer errors
2. Focus on one category of errors at a time
3. Update TypeScript compiler target if needed (many errors require ES2015+)
4. Ensure proper dependency management to avoid type conflicts

## Benefits

- **Consistency**: All packages use the same type-checking approach
- **CI Integration**: Automatic type checking prevents type errors from being merged
- **Developer Experience**: Simple `pnpm type-check` command for full project validation
- **Incremental**: Only includes packages that currently pass, allowing gradual improvement

## Future Work

- Fix remaining packages to include them in the type-check suite
- Consider stricter TypeScript configurations for better type safety
- Investigate automated type checking in development workflow