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tsx

TypeScript Execute (tsx): Node.js enhanced with esbuild to run TypeScript & ESM files

Features

Blazing fast on-demand TypeScript & ESM compilation
Works in both CommonJS and ESM packages
Supports next-gen TypeScript extensions (.cts & .mts)
Supports node: import prefixes
Hides experimental feature warnings
TypeScript REPL
Tested on Linux & Windows with Node.js v12~18

Install

Local installation

If you're using it in an npm project, install it as a development dependency:

npm install --save-dev tsx

You can reference it directly in the package.json#scripts object:

{
    "scripts": {
        "dev": "tsx ..."
    }
}

To use the binary, you can call it with npx while in the project directory:

npx tsx ...

Global installation

If you want to use it in any arbitrary project without npx, install it globally:

npm install --global tsx

You can call tsx directly:

tsx ...

Usage

Run TypeScript / ESM / CJS module

Pass in a file to run:

tsx ./file.ts

Watch mode

Run file and automatically re-run on changes.

All imported files are watched except from the following directories: node_modules, bower_components, vendor, dist, and .* (hidden directories).

Press Return to manually re-run.

tsx watch ./file.ts

REPL

Start a TypeScript REPL by running with no arguments.

tsx

Cache

Modules transformations are cached in the system cache directory (TMPDIR). Transforms are cached by content hash so duplicate dependencies are not re-transformed.

Set the --no-cache flag to disable the cache:

tsx --no-cache ./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 with Node.js, pass it into the --loader flag.

Note: Node.js's experimental feature warnings will not be suppressed when used as a loader

# As a CLI flag
node --loader tsx ./file.ts

# As an environment variable
NODE_OPTIONS='--loader tsx' node ./file.ts

Tip: In rare circumstances, you might be limited to use the -r, --require flag.
You can use @esbuild-kit/cjs-loader but transformations will only be applied to require().

Dependencies

@esbuild-kit/esm-loader - Node.js Loader to transform TypeScript to ESM.
@esbuild-kit/cjs-loader - Node.js requie() hook to transform TypeScript & ESM to CommonJS.

FAQ

Does it do type-checking?

No, esbuild does not support type checking.

It's recommended to run TypeScript separately as a command (tsc --noEmit) or via IDE IntelliSense.

How is `tsx` different from `ts-node`?

They are both tools to run TypeScript files.

The main difference is that tsx is powered by esbuild for blazing fast TypeScript compilation. Whereas ts-node uses the TypeScript compiler, which is not as fast.

Because esbuild doesn't do type checking, tsx is more equivalent to ts-node --transpileOnly.

If you migrated from ts-node, please share your performance gains here!