@zenyr/bun-pty


A cross-platform pseudo-terminal (PTY) implementation for Bun runtime, powered by Rust's portable-pty library and Bun's FFI capabilities.

> ⚠️ Bun Runtime Required: This package uses bun:ffi and Bun-specific APIs. For Node.js, please use node-pty instead.

> Note: This is a fork of bun-pty (v0.3.2) with significant improvements and architectural changes.

🔀 Fork Improvements (v0.3.3+)

This fork adds the following improvements over the original bun-pty:

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- Platform-specific packages: Split native libraries into optional dependencies (~600KB vs ~3-4MB)
- ARM64 support: Added native support for ARM64 on both Linux and macOS

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- Exit code handling: Fixed issue where child process exit codes were not properly captured
- FFI bindings: Corrected bun_pty_write FFI bindings and removed unnecessary null terminators
- Argument quoting: Fixed bash argument handling for commands with spaces and special characters

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- Enhanced error messages: Better library resolution errors with platform detection
- Custom library path: Support for BUN_PTY_LIB environment variable
- Comprehensive tests: Added exit code verification and vi integration tests
- Security: Pinned GitHub Actions versions and fixed workflow vulnerabilities

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- Cross-platform builds: Automated builds for all platforms (Linux/macOS/Windows, x64/ARM64)
- Multi-package publishing: Automated publishing of platform-specific packages to npm

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The following improvements have been submitted as pull requests to the upstream repository:

- #10 - Fix: Report actual process exit code instead of hardcoded 0 - Fixes exit code handling bug
- #11 - Fix bash -c argument handling and FFI bindings - Fixes argument quoting and FFI binding issues

These fixes are already included in this fork (v0.3.3+) and are pending review in the upstream repository.

🚀 Features

- Cross-platform - Works on macOS, Linux, and Windows
- Simple API - Clean Promise-based API similar to node-pty
- Type-safe - Complete TypeScript definitions included
- Efficient - Rust backend with proper error handling and multithreading
- Zero dependencies - No external JavaScript dependencies required
- Modern - Built specifically for Bun using its FFI capabilities

📦 Installation

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``bash
bun add @zenyr/bun-pty
`

The package automatically installs the correct native library for your platform. Platform-specific packages are installed as optional dependencies:

- @zenyr/bun-pty-linux-x64 - Linux x86_64
- @zenyr/bun-pty-linux-arm64 - Linux ARM64
- @zenyr/bun-pty-darwin-x64 - macOS x86_64 (Intel)
- @zenyr/bun-pty-darwin-arm64 - macOS ARM64 (Apple Silicon)
- @zenyr/bun-pty-win32-x64 - Windows x86_64

> Note: Only the platform-specific package matching your system will be downloaded, keeping installation size minimal (~600KB instead of ~3-4MB).

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Installing from GitHub requires building from source (Rust toolchain needed):

`bash
bun add github:zenyr/bun-pty --trust
`

Important: GitHub installations include source code and require the Rust toolchain (cargo) to build. Bun requires explicit permission to run build scripts. Use the --trust flag or add to trustedDependencies:

`json
{
"dependencies": {
"@zenyr/bun-pty": "github:zenyr/bun-pty"
},
"trustedDependencies": [
"@zenyr/bun-pty"
]
}
`

> Tip: For production use, prefer the npm package which includes prebuilt binaries and doesn't require Rust.

⚙️ Requirements

- Bun 1.0.0 or higher
- Rust toolchain (cargo) is required only when installing from GitHub or building from source
- TypeScript (included as devDependency)

📋 Platform Support

| Platform | Status | Notes |
|----------|--------|-------|
| macOS | ✅ | Fully supported |
| Linux | ✅ | Fully supported |
| Windows | ✅ | Fully supported |

🚦 Usage

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`typescript
import { spawn } from "@zenyr/bun-pty";

// Create a new terminal
const terminal = spawn("bash", [], {
name: "xterm-256color",
cols: 80,
rows: 24
});

// Handle data from the terminal
terminal.onData((data) => {
console.log("Received:", data);
});

// Handle terminal exit
terminal.onExit(({ exitCode, signal }) => {
console.log(Process exited with code ${exitCode} and signal ${signal});
});

// Write to the terminal
terminal.write("echo Hello from Bun PTY\n");

// Resize the terminal
terminal.resize(100, 40);

// Kill the process when done
setTimeout(() => {
terminal.kill();
}, 5000);
`

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The library includes complete TypeScript definitions. Here's how to use it with full type safety:

`typescript
import { spawn } from "@zenyr/bun-pty";
import type { IPty, IExitEvent, IPtyForkOptions } from "@zenyr/bun-pty";

// Create typed options
const options: IPtyForkOptions = {
name: "xterm-256color",
cols: 100,
rows: 30,
cwd: process.cwd()
};

// Create a terminal with proper typing
const terminal: IPty = spawn("bash", [], options);

// Typed event handlers
const dataHandler = terminal.onData((data: string) => {
process.stdout.write(data);
});

const exitHandler = terminal.onExit((event: IExitEvent) => {
console.log(Process exited with code: ${event.exitCode});
});

// Clean up when done
dataHandler.dispose();
exitHandler.dispose();
`

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`typescript
import { spawn } from "@zenyr/bun-pty";
import { createInterface } from "node:readline";

// Create a PTY running bash
const pty = spawn("bash", [], {
name: "xterm-256color",
cwd: process.cwd()
});

// Forward PTY output to stdout
pty.onData((data) => {
process.stdout.write(data);
});

// Send user input to the PTY
process.stdin.on("data", (data) => {
pty.write(data.toString());
});

// Handle PTY exit
pty.onExit(() => {
console.log("Terminal session ended");
process.exit(0);
});

// Handle SIGINT (Ctrl+C)
process.on("SIGINT", () => {
pty.kill();
});
`

📖 API Reference

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Creates and spawns a new pseudoterminal.

- file: The executable to launch
- args: Arguments to pass to the executable
- options: Configuration options
- name: Terminal name (e.g., "xterm-256color")
- cols: Number of columns (default: 80)
- rows: Number of rows (default: 24)
- cwd: Working directory (default: process.cwd())
- env: Environment variables

Returns an IPty instance.

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`typescript
interface IPty {
// Properties
readonly pid: number; // Process ID
readonly cols: number; // Current columns
readonly rows: number; // Current rows
readonly process: string; // Process name

// Events
onData: (listener: (data: string) => void) => IDisposable;
onExit: (listener: (event: IExitEvent) => void) => IDisposable;

// Methods
write(data: string): void; // Write data to terminal
resize(cols: number, rows: number): void; // Resize terminal
kill(signal?: string): void; // Kill the process
}
`

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`typescript
interface IExitEvent {
exitCode: number;
signal?: number | string;
}

interface IDisposable {
dispose(): void;
}
`

🔧 Building from Source

If you want to build the package from source:

`bash


Clone the repository

git clone https://github.com/zenyr/bun-pty.git
cd bun-pty

Install dependencies

bun install

Build Rust library and TypeScript

bun run build

Run tests

bun test
`

❓ Troubleshooting

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The npm package uses platform-specific optional dependencies to provide prebuilt binaries. Each platform package contains only the native library for that specific OS and architecture.

If you encounter issues with the prebuilt binaries:

1. Check if the platform package was installed:
`bash
ls node_modules/@zenyr/bun-pty-*/
`

2. Force reinstall the platform package:
`bash
bun add @zenyr/bun-pty --force
`

3. Build from source (development only):
`bash
cd node_modules/@zenyr/bun-pty
bun run build
`

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You can specify a custom path to the native library using the BUN_PTY_LIB environment variable:

`bash
export BUN_PTY_LIB=/path/to/librust_pty.dylib
bun run your-script.ts
`

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- Error: librust_pty shared library not found
- Make sure the appropriate platform package is installed
- Check that your OS and architecture match one of the supported platforms
- Try reinstalling with bun add @zenyr/bun-pty --force

- Error: Unable to load shared library
- Ensure you have the necessary system libraries installed
- On Linux, you may need libc6` and related dependencies

- Process spawn fails
- Check if you have the required permissions and paths
- Verify the executable exists and is in your PATH

📄 License

This project is licensed under the MIT License.

🙏 Credits

- Forked from bun-pty by @sursaone
- Built specifically for Bun
- Uses portable-pty from WezTerm for cross-platform PTY support
- Inspired by node-pty for the API design