# 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