ts-node

TypeScript execution environment for Node.js

TLDR

Run TypeScript file

$ ts-node [script.ts]

Start REPL

$ ts-node

Run with specific config

$ ts-node -P [tsconfig.json] [script.ts]

Transpile only (skip type checking)

$ ts-node --transpile-only [script.ts]

Run as ESM

$ ts-node --esm [script.ts]

Evaluate code

$ ts-node -e "console.log('Hello')"

Transpile with SWC (fastest mode)

$ ts-node --swc [script.ts]

Print evaluated expression

$ ts-node -p "1 + 1"

SYNOPSIS

ts-node [-P config] [--transpile-only] [--swc] [--esm] [options] [file] [args]

ts-node is a TypeScript execution engine for Node.js that compiles and runs TypeScript files on-the-fly without a separate build step. By default it performs full type checking at runtime, reporting type errors before execution begins.The --transpile-only mode skips type checking for significantly faster startup, which is useful during development when your editor already provides type feedback. The --swc flag uses the SWC transpiler (written in Rust) for an even greater speed improvement, and implies --transpileOnly. ESM mode (--esm) handles ES module imports and is needed when working with import/export syntax natively. The built-in REPL provides an interactive TypeScript environment for experimentation.Configuration is loaded from tsconfig.json by default, and a custom config can be specified with -P. The tool integrates well with development workflows using ts-node-dev or nodemon for automatic restart on file changes.

PARAMETERS

-P FILE

Path to tsconfig.json.

--transpile-only, -T

Skip type checking.

--esm

Use ESM loader.

-e CODE

Evaluate code.

-p CODE

Evaluate and print.

-r MODULE

Require module.

--pretty

Pretty-print errors.

--skip-project

Skip loading tsconfig.json.

--swc

Transpile with SWC for faster startup. Implies --transpileOnly.

--files

Load files, include, and exclude from tsconfig.json on startup.

-C NAME, --compiler NAME

TypeScript compiler to use (default: typescript).

-D CODES, --ignoreDiagnostics CODES

Ignore TypeScript diagnostics by code.

--emit

Write compiled output files to .ts-node directory.

-i, --interactive

Force REPL even if stdin is not a terminal.

--skipIgnore

Skip ignore checks, allowing compilation of files in node_modules.

-O JSON, --compilerOptions JSON

Merge JSON compiler options with tsconfig.

--showConfig

Print resolved tsconfig.json and exit.

CAVEATS

Slower startup than precompiled JavaScript. Type checking adds overhead. Some advanced TypeScript features need configuration. Not recommended for production.

HISTORY

ts-node was created around 2015 to enable direct TypeScript execution. It became essential for TypeScript development, enabling scripts, REPL, and development servers.