# TypeScript Node

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> TypeScript execution environment and REPL for node. **Works with `typescript@>=1.5`**.

## Installation

```sh
npm install -g ts-node

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

## Features

* Execute TypeScript files with node
* Interactive REPL
* Execute (and print) TypeScript through the CLI
* Uses source maps
* Loads compiler options and `.d.ts` files from `tsconfig.json`

## Usage

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

# Starts the TypeScript REPL.
ts-node

# 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](https://github.com/TypeStrong/ts-node/raw/master/screenshot.png)

### Programmatic

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

### Mocha

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

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

### Tape

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

### Gulp

```sh
# Just create a `gulpfile.ts` and run `gulp`.
gulp
```

## How It Works

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

**P.S.** This means that if you don't register an extension, it'll be 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 `--no-project` to skip loading `tsconfig.json`.

**NOTE**: You can use `ts-node` together with [tsconfig-paths](https://www.npmjs.com/package/tsconfig-paths) to load modules according to the `paths` section in `tsconfig.json`.

## Configuration Options

You can set options by passing them in before the script.

**Note:** These are in addition to the [node.js CLI arguments](https://nodejs.org/api/cli.html).

```sh
ts-node --compiler ntypescript --project src --ignoreWarnings 2304 hello-world.ts
```

* **--project, -P** Path to load TypeScript configuration from (JSON file, a directory containing `tsconfig.json`, or `--no-project`/`false` to disable) (also `process.env.TS_NODE_PROJECT`)
* **--compiler, -C** Use a custom, require-able TypeScript compiler compatible with `typescript@>=1.5.0-alpha` (also `process.env.TS_NODE_COMPILER`)
* **--ignore** Specify an array of regular expression strings for `ts-node` to skip compiling as TypeScript (defaults to `/node_modules/`, `--no-ignore`/`false` to disable) (also `process.env.TS_NODE_IGNORE`)
* **--ignoreWarnings, -I** Set an array of TypeScript diagnostic codes to ignore (also `process.env.TS_NODE_IGNORE_WARNINGS`)
* **--compilerOptions, -O** Set compiler options using JSON (E.g. `--compilerOptions '{"target":"es6"}'`) (also `process.env.TS_NODE_COMPILER_OPTIONS`)
* **--type-check** Use TypeScript with type checking (also `process.env.TS_NODE_TYPE_CHECK`)
* **--no-cache** Skip hitting the compiled JavaScript cache (also `process.env.TS_NODE_CACHE`)
* **--cache-directory** Configure the TypeScript cache directory (also `process.env.TS_NODE_CACHE_DIRECTORY`)

Additionally, the `transformers` option may be provided when programmatically registering `ts-node` to specify custom TypeScript transformers.

## License

MIT

[npm-image]: https://img.shields.io/npm/v/ts-node.svg?style=flat
[npm-url]: https://npmjs.org/package/ts-node
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[travis-url]: https://travis-ci.org/TypeStrong/ts-node
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