# tsx
_TypeScript Execute (tsx)_: The easiest way to run TypeScript in Node.js
### Features
- Super fast!
- TypeScript REPL
- Supports `tsconfig.json` [`paths`](https://www.typescriptlang.org/tsconfig#paths)
- Works in both [CommonJS and ESM packages](https://nodejs.org/api/packages.html#type)
> [!TIP]
> **Build your TypeScript projects?**
>
> Try [ pkgroll](https://github.com/privatenumber/pkgroll)—the zero-config package bundler used by _tsx_!
>
> _pkgroll_ is a thin Rollup wrapper that makes it so simple for your package to support CommonJS, ESM, & TypeScript.
>
> If you love tsx, you'll love pkgroll too!
## About
`tsx` is a CLI command you can use just like you would use `node`:
Before
After
```sh
node file.js
```
```sh
tsx file.js
```
Use it to enhance your Node.js experience:
- _Just run_ TypeScript code without configuration
- Seamless integration between CommonJS and ES Modules
You'll never get the following error again:
```
Error [ERR_REQUIRE_ESM]: require() of ES Module from ./file.js not supported.
Instead change the require of in ./file.js to a dynamic import() which is available in all CommonJS modules.
```
### ⚡️ Quick start
Try it out without setup using [npx](https://docs.npmjs.com/cli/v8/commands/npx)! Just pass in a TypeScript file:
```sh
npx tsx ./script.ts
```
## Installation
### Local installation
To add tsx to an npm project as a development dependency:
```sh
npm install --save-dev tsx
```
You can reference it directly in the `package.json#scripts` object (you don't need `npx` here):
```json5
{
"scripts": {
"dev": "tsx ./file.ts"
}
}
```
To use the binary, you can call it with [`npx`](https://docs.npmjs.com/cli/v8/commands/npx) while in the project directory:
```sh
npx tsx ...
```
### Global installation
If you want to use tsx anywhere on your computer without [`npx`](https://docs.npmjs.com/cli/v8/commands/npx), install it globally:
```sh
npm install --global tsx
```
Then, you can call `tsx` directly:
```sh
tsx file.ts
```
Now you can replace `node ...` with `tsx ...` in all your commands!
## Usage
### Swap `node` out for `tsx`
_tsx_ is an enhanced version of Node.js. If you have a `node ...` command, you can replace the `node` with `tsx` and it will just work.
Because it's a drop-in replacement for `node`, it supports all [Node.js command-line flags](https://nodejs.org/docs/latest-v20.x/api/cli.html).
```sh
# Old command
node --no-warnings --env-file=.env ./file.js
# New command
tsx --no-warnings --env-file=.env ./file.js
```
#### Custom `tsconfig.json` path
By default, `tsconfig.json` will be detected from the current working directory.
To set a custom path, use the `--tsconfig` flag:
```sh
tsx --tsconfig ./path/to/tsconfig.custom.json ./file.ts
```
Alternatively, use the `TSX_TSCONFIG_PATH` environment variable:
```sh
TSX_TSCONFIG_PATH=./path/to/tsconfig.custom.json tsx ./file.ts
```
### Watch mode
Run file and automatically rerun on changes:
```sh
tsx watch ./file.ts
```
All imported files are watched except from the following directories:
`node_modules`, `bower_components`, `vendor`, `dist`, and `.*` (hidden directories).
#### Ignore files from watch
To exclude files from being watched, pass in a path or glob to the `--ignore` flag:
```sh
tsx watch --ignore ./ignore-me.js --ignore ./ignore-me-too.js ./file.ts
```
#### Tips
- Press Return to manually rerun
- Pass in `--clear-screen=false` to disable clearing the screen on rerun
### REPL
Start a TypeScript REPL by running with no arguments:
```sh
tsx
```
### Cache
Modules transformations are cached in the system cache directory ([`TMPDIR`](https://en.wikipedia.org/wiki/TMPDIR)). Transforms are cached by content hash, so duplicate dependencies are not re-transformed.
Set the `--no-cache` flag to disable the cache:
```sh
tsx --no-cache ./file.ts
```
Alternatively, use the `TSX_DISABLE_CACHE` environment variable:
```sh
TSX_DISABLE_CACHE=1 tsx ./file.ts
```
### Node.js Loader
`tsx` is a standalone binary designed to be used in place of `node`, but sometimes you'll want to use `node` directly. For example, when adding TypeScript & ESM support to npm-installed binaries.
To use `tsx` as a Node.js loader, pass it in to the [`--import`](https://nodejs.org/api/module.html#enabling) flag. This will add TypeScript & ESM support for both Module and CommonJS contexts.
```sh
node --import tsx ./file.ts
```
Or as an environment variable:
```sh
NODE_OPTIONS='--import tsx' node ./file.ts
```
> **Note:** The loader is limited to adding support for loading TypeScript/ESM files. CLI features such as _watch mode_ or suppressing "experimental feature" warnings will not be available.
#### ESM only loader
If you only need to add TypeScript support in a Module context, you can use the ESM loader:
##### Node.js v20.6.0 and above
```sh
node --import tsx/esm ./file.ts
```
##### Node.js v20.5.1 and below
```sh
node --loader tsx/esm ./file.ts
```
#### CommonJS only loader
If you only need to add TypeScript & ESM support in a CommonJS context, you can use the CJS loader:
```sh
node --require tsx/cjs ./file.ts
```
### Hashbang
If you prefer to write scripts that doesn't need to be passed into tsx, you can declare it in the [hashbang](https://bash.cyberciti.biz/guide/Shebang).
Simply add `#!/usr/bin/env tsx` at the top of your file:
_file.ts_
```ts
#!/usr/bin/env tsx
console.log('argv:', process.argv.slice(2))
```
And make the file executable:
```sh
chmod +x ./file.ts
```
Now, you can run the file without passing it into tsx:
```sh
$ ./file.ts hello
argv: [ 'hello' ]
```
### VS Code debugging
#### Setup
Create the following configuration file in your project to setup debugging in VS Code:
`.vscode/launch.json`
```json5
{
"version": "0.2.0",
"configurations": [
/*
Each config in this array is an option in the debug drop-down
See below for configurations to add...
*/
],
}
```
#### Debugging method 1: Run tsx directly from VSCode
1. Add the following configuration to the `configurations` array in `.vscode/launch.json`:
```json5
{
"name": "tsx",
"type": "node",
"request": "launch",
// Debug current file in VSCode
"program": "${file}",
/*
Path to tsx binary
Assuming locally installed
*/
"runtimeExecutable": "${workspaceFolder}/node_modules/.bin/tsx",
/*
Open terminal when debugging starts (Optional)
Useful to see console.logs
*/
"console": "integratedTerminal",
"internalConsoleOptions": "neverOpen",
// Files to exclude from debugger (e.g. call stack)
"skipFiles": [
// Node.js internal core modules
"/**",
// Ignore all dependencies (optional)
"${workspaceFolder}/node_modules/**",
],
}
```
2. In VSCode, open the file you want to run
3. Go to VSCode's debug panel, select "tsx" in the drop down, and hit the play button (F5).
#### Debugging method 2: Attach to a running Node.js process
> This method works for any Node.js process and it's not specific to tsx
1. Add the following configuration to the `configurations` array in `.vscode/launch.json`:
```json
{
"name": "Attach to process",
"type": "node",
"request": "attach",
"port": 9229,
"skipFiles": [
// Node.js internal core modules
"/**",
// Ignore all dependencies (optional)
"${workspaceFolder}/node_modules/**",
],
}
```
2. Run tsx with `--inspect-brk` in a terminal window:
```sh
tsx --inspect-brk ./your-file.ts
```
3. Go to VSCode's debug panel, select "Attach to process" in the drop down, and hit the play button (F5).
See the [VSCode documentation on _Launch Configuration_](https://code.visualstudio.com/docs/nodejs/nodejs-debugging#_launch-configuration) for more information.
## Contributing & Support
If you're interested in contributing, please check out the [Contribution Guide](/CONTRIBUTING.md). Your collaboration will be greatly appreciated!
If you're encountering a problem, take advantage of my [_Priority Support_ service](https://github.com/sponsors/privatenumber) for as little as $25. I'd be happy to help you out! 🙂
## FAQ
### Why is it named _tsx_?
`tsx` stands for "TypeScript execute". Mirroring [`npx`](https://docs.npmjs.com/cli/v8/commands/npx), which stands for "Node.js package execute".
The 3-character package name offers an elegant developer experience, allowing usage like: `npx tsx ...`.
Unfortunately, it overlaps with React's [TSX/JSX](https://www.typescriptlang.org/docs/handbook/jsx.html), which stands for "TypeScript XML".
### Does it type check the code it runs?
No. tsx is designed to be a simple TypeScript runner.
If you need type-checking, you can use an IDE like [VS Code](https://code.visualstudio.com) and it will type-check as you code via [IntelliSense](https://code.visualstudio.com/docs/languages/typescript). Alternatively, you can run the TypeScript Compiler only for type-checking (e.g. `tsc --noEmit`) as a linting step.
### How is `tsx` different from [`ts-node`](https://github.com/TypeStrong/ts-node)?
`tsx` and `ts-node` are both designed for executing TypeScript files in Node.js, but offer different approaches to suit user preferences.
- **Simple installation** tsx is offered as a single binary without peer dependencies, and can be used without installation: `npx tsx ./script.ts`. In comparison, `ts-node` requires installing TypeScript or SWC as peer dependencies.
- **Zero configuration** tsx _just works_. It doesn't require initial setup or a `tsconfig.json` file, and doesn't get in the way of running your code.
- **Sensible defaults** tsx employs sensible defaults based on file imports and Node.js version, removing the need for certain `tsconfig.json` settings (that are designed for compilation rather than runtime). In comparison, ts-node relies on TypeScript's defaults (e.g. [`ES3` target](https://www.typescriptlang.org/tsconfig#target)), which may be outdated.
- **Module adaptability** tsx automatically adapts between CommonJS and ESM modules, even supporting `require()` of ESM modules, facilitating a smoother transition as the Node.js ecosystem evolves.
- **Enhancements** tsx gracefully handles [new JS & TS syntax](https://esbuild.github.io/content-types/) and features based on the Node.js version. It also supports [`tsconfig.json` paths](https://www.typescriptlang.org/tsconfig#paths) out of the box.
- **Speed** tsx utilizes [esbuild](https://esbuild.github.io/faq/#:~:text=typescript%20benchmark) to achieve rapid TypeScript compilation. In comparison, ts-node uses the TypeScript compiler by default. Because tsx doesn't type check, it's similar to `ts-node --esm --swc` (which uses the [SWC compiler](https://github.com/TypeStrong/ts-node#swc-1)).
- **Watcher** As a DX bonus, tsx also comes with watch mode to help you iterate faster!
For a detailed technical comparison, you can refer to this [exhaustive comparison](https://github.com/privatenumber/ts-runtime-comparison) between `tsx`, `ts-node`, and other runtimes.
### Does it have a configuration file?
No. tsx's integration with Node.js is designed to be simple & seamless. However, it supports a few properties from `tsconfig.json` to determine how to compile TypeScript files.
### Does it have any limitations?
TypeScript & ESM transformations are handled by [esbuild](https://esbuild.github.io/), so it shares the same limitations such as:
- Compatibility with code executed via `eval()` is not preserved
- Only [certain `tsconfig.json` properties](https://esbuild.github.io/content-types/#tsconfig-json) are supported
- [`emitDecoratorMetadata`](https://www.typescriptlang.org/tsconfig#emitDecoratorMetadata) is not supported
For details, refer to esbuild's [JavaScript caveats](https://esbuild.github.io/content-types/#javascript-caveats) and [TypeScript caveats](https://esbuild.github.io/content-types/#typescript-caveats) documentation.
## Sponsors
pkgroll](https://github.com/privatenumber/pkgroll)—the zero-config package bundler used by _tsx_!
>
> _pkgroll_ is a thin Rollup wrapper that makes it so simple for your package to support CommonJS, ESM, & TypeScript.
>
> If you love tsx, you'll love pkgroll too!
