README.md•6.43 kB
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# The nodemon for TypeScript
`tsc-watch` starts the installed TypeScript compiler (`tsc`) 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.
**Anything that you can do with `tsc` you can do with `tsc-watch`, the only difference is that `tsc-watch` can react to compilation status.**
| Argument | Description |
| --------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| `--onSuccess COMMAND` | Executes `COMMAND` on **every successful** compilation. |
| `--onFirstSuccess COMMAND` | Executes `COMMAND` on the **first successful** compilation. |
| `--onEmit COMMAND` | Executes debounced `COMMAND` on **every emitted file**, ignoring unchanged files and disregards compilation success or failure. |
| `--onEmitDebounceMs DELAY` | Delay by which to debounce `--onEmit` (default: 300). |
| `--onFailure COMMAND` | Executes `COMMAND` on **every failed** compilation. |
| `--onCompilationStarted COMMAND` | Executes `COMMAND` on **every compilation start** event (initial and incremental). |
| `--onCompilationComplete COMMAND` | Executes `COMMAND` on **every successful or failed** compilation. |
| `--maxNodeMem` | Calls `node` with a specific memory limit `max_old_space_size`, to use if your project needs more memory. |
| `--noColors` | By default tsc-watch adds colors the output with green<br>on success, and in red on failure. <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. |
| `--signalEmittedFiles` | Will run `tsc` compiler with `--listEmittedFiles`, but hiding TSFILE lines. Use it to enable `file_emitted` event, while keeping tsc stdout silent. |
| `--silent` | Do not print any messages on stdout. |
| `--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
```
```sh
## for command-line usage
npm install -g typescript tsc-watch
```
## 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"
## Watching 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 npm script
```
"dev-server": "tsc-watch --noClear -p ./src/tsconfig.json --onSuccess \"node ./dist/server.js\"",
```
### From javascript
You can see a detailed example [here](https://github.com/gilamran/tsc-watch/blob/master/tsc-watch-client-example.js)
The client is implemented as an instance of `Node.JS`'s `EventEmitter`, with the following events:
- `started` - Emitted upon the compilation start (initial or incremental).
- `first_success` - Emitted upon first successful compilation.
- `subsequent_success` - Emitted upon every subsequent successful compilation.
- `compile_errors` - Emitted upon every failing compilation.
- `file_emitted` - Emitted upon every file transpiled if `--listEmittedFiles` is used.
Once subscribed to the relevant events, start the client by running `watch.start()`
To kill the client, run `watch.kill()`
Example usage:
```javascript
// Using CommonJS:
const { TscWatchClient } = require('tsc-watch/client');
// Using ES6 import:
import { TscWatchClient } from 'tsc-watch/client';
const watch = new TscWatchClient();
watch.on('started', () => {
console.log('Compilation started');
});
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.
- The (`onEmit`) `COMMAND` will not run if the compilation succeeded with no changed files, unless it is the first success.
- The (`onEmit`) `COMMAND` will run even if the compilation failed, but emitted changed files.
- The (`onEmit`) `COMMAND` will not run 100 times for 100 files, due to `--onEmitDebounce`
- The (`onEmit`) `COMMAND` is not cancelling the `onSuccess`/`onFirstSuccess`/`onFailure`/`onCompilationComplete`/`onCompilationStarted` commands and vice versa.
- `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.