TypeScript execution environment and REPL for node

typescript, node, runtime, environment, ts, compiler, nodejs, repl
npm install ts-node@6.0.0


TypeScript Node

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TypeScript execution environment and REPL for node. Works with typescript@>=2.0.


npm install -g ts-node

# Install a TypeScript compiler (requires `typescript` by default).
npm install -g typescript


  • Execute TypeScript files with node
  • Interactive REPL
  • Execute (and print) TypeScript through the CLI
  • Source map support
  • Loads compiler options and .d.ts files from tsconfig.json


# Execute a script as you would normally with `node`.
ts-node script.ts

# Starts the TypeScript REPL.

# Execute code with TypeScript.
ts-node -e 'console.log("Hello, world!")'

# Execute, and print, code with TypeScript.
ts-node -p '"Hello, world!"'

# Pipe scripts to execute with TypeScript.
echo "console.log('Hello, world!')" | ts-node

TypeScript REPL


You can require ts-node and register the loader for future requires by using require('ts-node').register({ /* options */ }). You can also use the shortcuts node -r ts-node/register or node -r ts-node/register/type-check depending on your preferences.

Note: If you need to use advanced node.js CLI arguments, use node -r ts-node/register instead of the ts-node CLI.


mocha --require ts-node/register --watch-extensions ts,tsx "test/**/*.{ts,tsx}" [...args]

Note: --watch-extensions is only used in --watch mode.


ts-node node_modules/tape/bin/tape [...args]


# Create a `gulpfile.ts` and run `gulp`.

How It Works

TypeScript Node works by registering the TypeScript compiler for the .ts, .tsx and, with allowJs enabled, .js extensions. When node.js has a file extension registered (the require.extensions object), it will use the extension internally for module resolution. When an extension is unknown to node.js, it will handle the file as .js (JavaScript).

P.S. This means if you don't register an extension, it is compiled as JavaScript. When ts-node is used with allowJs, JavaScript files are transpiled using the TypeScript compiler.

Loading tsconfig.json

Typescript Node uses tsconfig.json automatically, use --skip-project to skip loading tsconfig.json.

NOTE: You can use ts-node together with tsconfig-paths to load modules according to the paths section in tsconfig.json.

Configuration Options

You can set options by passing them before the script path, via programmatic usage or via environment variables.

ts-node --compiler ntypescript --project src/tsconfig.json hello-world.ts

CLI Options

Support --print, --eval and --require from node.js CLI options.

  • --help Prints help text
  • --version Prints version information

CLI and Programmatic Options

Environment variable denoted in parentheses.

  • --typeCheck Enable type checking for TypeScript (TS_NODE_TYPE_CHECK)
  • --cacheDirectory Configure the output file cache directory (TS_NODE_CACHE_DIRECTORY)
  • -I, --ignore [pattern] Override the path patterns to skip compilation (TS_NODE_IGNORE)
  • -P, --project [path] Path to TypeScript JSON project file (TS_NODE_PROJECT)
  • -C, --compiler [name] Specify a custom TypeScript compiler (TS_NODE_COMPILER)
  • -D, --ignoreDiagnostics [code] Ignore TypeScript warnings by diagnostic code (TS_NODE_IGNORE_DIAGNOSTICS)
  • -O, --compilerOptions [opts] JSON object to merge with compiler options (TS_NODE_COMPILER_OPTIONS)
  • --no-cache Disable the local TypeScript Node cache (TS_NODE_CACHE)
  • --skip-project Skip project config resolution and loading (TS_NODE_SKIP_IGNORE)
  • --skip-ignore Skip ignore checks (TS_NODE_SKIP_PROJECT)

Programmatic Only Options

  • transformers An array of transformers to pass to TypeScript
  • readFile Custom TypeScript-compatible file reading function
  • fileExists Custom TypeScript-compatible file existence function