TypeScript execution and REPL for node.js, with source map support. Works with
typescript@>=2.0
.
Installation
# Locally in your project.
npm install -D ts-node
npm install -D typescript
# Or globally with TypeScript.
npm install -g ts-node
npm install -g typescript
Tip: Installing modules locally allows you to control and share the versions through package.json
. TS Node will always resolve the compiler from cwd
before checking relative to its own installation.
Usage
# Execute a script as `node` + `tsc`.
ts-node script.ts
# Starts a TypeScript REPL.
ts-node
# Execute code with TypeScript.
ts-node -e 'console.log("Hello, world!")'
# Execute, and print, code with TypeScript.
ts-node -p -e '"Hello, world!"'
# Pipe scripts to execute with TypeScript.
echo "console.log('Hello, world!')" | ts-node
Programmatic
You can require ts-node
and register the loader for future requires by using require('ts-node').register({ /* options */ })
. You can also use file shortcuts - node -r ts-node/register
or node -r ts-node/register/transpile-only
- depending on your preferences.
Note: If you need to use advanced node.js CLI arguments (e.g. --inspect
), use them with node -r ts-node/register
instead of the ts-node
CLI.
Mocha
mocha --require ts-node/register --watch-extensions ts,tsx "test/**/*.{ts,tsx}" [...args]
Note: --watch-extensions
is only used in --watch
mode.
Tape
ts-node node_modules/tape/bin/tape [...args]
Gulp
# Create a `gulpfile.ts` and run `gulp`.
gulp
Visual Studio Code
Create a new node.js configuration, add -r ts-node/register
to node args and move the program
to the args
list (so VS Code doesn't look for outFiles
).
{
"type": "node",
"request": "launch",
"name": "Launch Program",
"runtimeArgs": [
"-r",
"ts-node/register"
],
"args": [
"${workspaceFolder}/index.ts"
]
}
Note: If you are using the --project <tsconfig.json>
command line argument as per the Configuration Options, and want to apply this same behavior when launching in VS Code, add an "env" key into the launch configuration: "env": { "TS_NODE_PROJECT": "<tsconfig.json>" }
.
How It Works
TypeScript Node works by registering the TypeScript compiler for .tsx?
and .jsx?
(when allowJs == true
) extensions. When node.js has an extension registered (via require.extensions
), it will use the extension internally for module resolution. When an extension is unknown to node.js, it handles the file as .js
(JavaScript). By default, TypeScript Node avoids compiling files in /node_modules/
for three reasons:
- Modules should always be published in a format node.js can consume
- Transpiling the entire dependency tree will make your project slower
- Differing behaviours between TypeScript and node.js (e.g. ES2015 modules) can result in a project that works until you decide to support a feature natively from node.js
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.
tsconfig.json
Loading Typescript Node loads tsconfig.json
automatically. Use --skip-project
to skip loading the tsconfig.json
.
Tip: 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
Supports --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.
-T, --transpile-only
Use TypeScript's fastertranspileModule
(TS_NODE_TRANSPILE_ONLY
, default:false
)-I, --ignore [pattern]
Override the path patterns to skip compilation (TS_NODE_IGNORE
, default:/node_modules/
)-P, --project [path]
Path to TypeScript JSON project file (TS_NODE_PROJECT
)-C, --compiler [name]
Specify a custom TypeScript compiler (TS_NODE_COMPILER
, default:typescript
)-D, --ignore-diagnostics [code]
Ignore TypeScript warnings by diagnostic code (TS_NODE_IGNORE_DIAGNOSTICS
)-O, --compiler-options [opts]
JSON object to merge with compiler options (TS_NODE_COMPILER_OPTIONS
)--files
Load files fromtsconfig.json
on startup (TS_NODE_FILES
, default:false
)--pretty
Use pretty diagnostic formatter (TS_NODE_PRETTY
, default:false
)--skip-project
Skip project config resolution and loading (TS_NODE_SKIP_PROJECT
, default:false
)--skip-ignore
Skip ignore checks (TS_NODE_SKIP_IGNORE
, default:false
)--log-error
Logs errors of types instead of exit the process (TS_NODE_LOG_ERROR
, default:false
)
Programmatic Only Options
transformers
An array of transformers to pass to TypeScriptreadFile
Custom TypeScript-compatible file reading functionfileExists
Custom TypeScript-compatible file existence function
Help! My Types Are Missing!
TypeScript Node does not use files
, include
or exclude
, by default. This is because a large majority projects do not use all of the files in a project directory (e.g. Gulpfile.ts
, runtime vs tests) and parsing every file for types slows startup time. Instead, ts-node
starts with the script file (e.g. ts-node index.ts
) and TypeScript resolves dependencies based on imports and references.
For global definitions, you can use the typeRoots
compiler option. This requires that your type definitions be structured as type packages (not loose TypeScript definition files). More details on how this works can be found in the TypeScript Handbook.
Example tsconfig.json
:
{
"compilerOptions": {
"typeRoots" : ["./node_modules/@types", "./typings"]
}
}
Example project structure:
<project_root>/
-- tsconfig.json
-- typings/
-- <module_name>/
-- index.d.ts
Example module declaration file:
declare module '<module_name>' {
// module definitions go here
}
For module definitions, you can use paths
:
{
"compilerOptions": {
"baseUrl": ".",
"paths": {
"custom-module-type": ["types/custom-module-type"]
}
}
}
An alternative approach for definitions of third-party libraries are triple-slash directives. This may be helpful if you prefer not to change your TypeScript compilerOptions
or structure your custom type definitions when using typeRoots
. Below is an example of the triple-slash directive as a relative path within your project:
/// <reference types="./types/untyped_js_lib" />
import UntypedJsLib from "untyped_js_lib"
Tip: If you must use files
, enable --files
flags or set TS_NODE_FILES=true
.
Watching and Restarting
TypeScript Node compiles source code via require()
, watching files and code reloads are out of scope for the project. If you want to restart the ts-node
process on file change, existing node.js tools such as nodemon, onchange and node-dev work.
There's also ts-node-dev
, a modified version of node-dev
using ts-node
for compilation and won't restart the process on file change.
License
MIT