svelte-check-rs

A high-performance, Rust-powered diagnostic engine designed as a drop-in replacement for svelte-check.

Note: This tool only supports Svelte 5+. For Svelte 4 or earlier, use the official svelte-check.

Features

• 🚀 Fast: 10-100x faster than svelte-check through Rust's zero-cost abstractions and parallel processing
• ✅ Accurate: Matches svelte-check diagnostics, including Svelte compiler errors via bun
• 🔄 Compatible: Drop-in CLI replacement, identical output formats
• 🔧 Maintainable: Clean separation of concerns, comprehensive test suite

Installation

npm (recommended)

npm install -D svelte-check-rs

The npm package uses platform-specific optional dependencies to provide the binary. If you install with --no-optional, re-enable optional dependencies or use the shell/PowerShell installers below.

Then add to your package.json scripts:

{
  "scripts": {
    "check": "svelte-check-rs"
  }
}

Or run directly with npx:

npx svelte-check-rs

macOS / Linux

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/pheuter/svelte-check-rs/releases/latest/download/svelte-check-rs-installer.sh | sh

Windows (PowerShell)

irm https://github.com/pheuter/svelte-check-rs/releases/latest/download/svelte-check-rs-installer.ps1 | iex

Usage

# Check current directory
svelte-check-rs

# Check specific directory
svelte-check-rs --workspace ./my-project

# Watch mode
svelte-check-rs --watch

# Different output formats
svelte-check-rs --output json
svelte-check-rs --output machine
svelte-check-rs --output human-verbose

Requirements

svelte-check-rs expects tsgo to be available from your workspace node_modules. Install it via:

npm install -D @typescript/native-preview

Some package managers (for example, bun) may auto-install peer dependencies, but explicit installation is always supported.

CLI Options

| Option | Description | |--------|-------------| | --workspace <PATH> | Working directory (default: .) | | --output <FORMAT> | Output format: human, human-verbose, json, machine | | --tsconfig <PATH> | Path to tsconfig.json | | --threshold <LEVEL> | Minimum severity: error, warning | | --watch | Watch mode | | --preserveWatchOutput | Don't clear screen in watch mode | | --fail-on-warnings | Exit with error on warnings | | --ignore <PATTERNS> | Glob patterns to ignore | | --skip-tsgo | Skip TypeScript type-checking | | --tsgo-version | Show installed tsgo version + path | | --bun-version | Show installed bun version + path | | --bun-update[=<VER>] | Update bun to latest or specific version | | --debug-paths | Show resolved binaries (tsgo, bun, svelte-kit) |

Caching: svelte-check-rs writes transformed files and tsgo incremental build info to node_modules/.cache/svelte-check-rs/. Cache invalidation is automatic: dependency changes (lockfiles, node_modules markers) clear the entire cache, and source file changes are handled via content-addressed writes.

Project Structure

crates/
├── svelte-parser/        # Lexer + parser + AST types
├── source-map/           # Position tracking and mapping
├── svelte-transformer/   # Svelte → TypeScript transformation
├── svelte-diagnostics/   # A11y and component checks
├── tsgo-runner/          # tsgo process management
├── bun-runner/           # bun-managed Svelte compiler bridge
└── svelte-check-rs/      # CLI binary

Development

# Build all crates
cargo build

# Run tests
cargo test

# Run clippy
cargo clippy --all-targets -- -D warnings

# Format code
cargo fmt

License

MIT License - see LICENSE for details.