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# The nodemon for TypeScript

`tsc-watch` starts a TypeScript compiler with `--watch` parameter, with the ability to react to compilation status.
`tsc-watch` was created to allow an easy dev process with TypeScript. Commonly used to restart a node server, similar to nodemon but for TypeScript.

| Argument | Description |
|-----------------------------------|--------------------------------------------------------------------------------------------------------------------------------------|
| `--onSuccess COMMAND` | Executes `COMMAND` on **every successful** compilation. |
| `--onFirstSuccess COMMAND` | Executes `COMMAND` on the **first successful** compilation. |
| `--onFailure COMMAND` | Executes `COMMAND` on **every failed** compilation. |
| `--onCompilationComplete COMMAND` | Executes `COMMAND` on **every successful or failed** compilation. |
| `--noColors` | By default tsc-watch adds colors the output with green<br>on success, and in red on failiure. <br>Add this argument to prevent that. |
| `--noClear` | In watch mode the `tsc` compiler clears the screen before reporting<br>Add this argument to prevent that. |
| `--compiler PATH` | The `PATH` will be used instead of typescript compiler.<br>Default is `typescript/bin/tsc` |

Notes:

* That all the above `COMMAND`s will be killed on process exit. (Using `SIGTERM`)
  
* A `COMMAND` is a single command and not multi command like `script1.sh && script2.sh`
  
* Any child process (`COMMAND`) will be terminated before creating a new one.

## Install

```sh
npm install tsc-watch --save-dev
```

## Usage

### From Command-Line

```sh
## Watching a project (with tsconfig.json)
tsc-watch --onSuccess "node ./dist/server.js"

## Beep on failure
tsc-watch --onFailure "echo Beep! Compilation Failed"

## Wathcing a single file
tsc-watch server.ts --outDir ./dist --onSuccess "node ./dist/server.js"

## Custom compiler
tsc-watch --onSuccess "node ./dist/server.js" --compiler my-typescript/bin/tsc
```

### From Code

The client is implemented as an instance of `Node.JS`'s `EventEmitter`, with the following events:

- `first_success` - Emitted upon first successful compilation.
- `subsequent_success` - Emitted upon every subsequent successful compilation.
- `compile_errors` - Emitted upon every failing compilation.

Once subscribed to the relevant events, start the client by running `watch.start()`

To kill the client, run `watch.kill()`

Example usage:

```javascript
const TscWatchClient = require('tsc-watch/client');
const watch = new TscWatchClient();

watch.on('first_success', () => {
  console.log('First success!');
});

watch.on('success', () => {
  // Your code goes here...
});

watch.on('compile_errors', () => {
  // Your code goes here...
});

watch.start('--project', '.');

try {
  // do something...
} catch (e) {
  watch.kill(); // Fatal error, kill the compiler instance.
}
```

Notes:

- The (`onSuccess`) `COMMAND` will not run if the compilation failed.
- `tsc-watch` is using the currently installed TypeScript compiler.
- `tsc-watch` is not changing the compiler, just adds the new arguments, compilation is the same, and all other arguments are the same.