The TypeScript compiler with --watch and a new onSuccess argument

tsc-watch starts the tsc (TypeScript compiler) with --watch parameter, there are 3 new arguments.

• --onSuccess COMMAND - The COMMAND will be executed on every successful TypeScript compilation, and killed on the next success.
• --onFirstSuccess COMMAND - The COMMAND will be executed only one time, on the first successful TypeScript compilation.
• --onFailure COMMAND - The COMMAND will be executed on failed TypeScript compilation.
• --noColors - tsc-watch colors the output with green on success, and in red on failiure. Add this argument to prevent that.

All above COMMANDs will be killed on process exit

Install

npm install tsc-watch --save-dev

Usage

From Command-Line

tsc-watch server.ts --outDir ./dist --onSuccess "node ./dist/server.js" --onFailure "echo Beep! Compilation Failed"

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:

const watch = require('tsc-watch/client');

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

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

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

watch.start();

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

Notes:

• The (onSuccess) COMMAND will not run if the compilation failed.
• Any child process (COMMAND) will be terminated before creating a new one.
• 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.
• tsc-watch was created to allow an easy dev process with TypeScript. Commonly used to restart a node server.