es-node-runner/lib/watcher.js

Node runner that transpiles typescript or es modules using blazing fast ⚡ esbuild and restarts the process automatically on change. Suitable for node development server.

import {watch} from 'chokidar';
import DEBUG from 'debug';
import {performance} from 'perf_hooks';
import {spawnOptions, watchOptions} from './config.js';
import {rebuild, initialBuild} from './transpiler.js';
import {logger} from './utils/index.js';
const debug = DEBUG('es-node-runner:watcher');
const {delay, restartCmd, clearTerminal, autoRestart} = spawnOptions;
function clearTerminalOutput() {
  process.stdout.write('\x1Bc\x1B[3J');
  debug(`Terminal output cleared`);
}
function restartSubProcess() {
  global.SUB_PROCESS_RESTART_TIME = performance.now();
  rebuild();
}
function restartOnChange(action) {
  debug(`${action}`);
  if (clearTerminal === true) {
    clearTerminalOutput();
  }
  logger.alert(
    `\n[Watcher]: ${action}\n` + `Sub process will restart after ${delay} ms\n`
  );
  restartSubProcess();
}
process.stdin.on('data', (data) => {
  const cmd = data.toString().trimEnd();
  switch (cmd) {
    case restartCmd:
      logger.alert(`\nreceived '${cmd}' cmd, restarting sub process...\n`);
      restartSubProcess();
      break;
    case 'clear':
      clearTerminalOutput();
      break;
    default:
      logger.warn(`unrecognized '${cmd}' cmd`);
      break;
  }
});
export default autoRestart === false
  ? () => initialBuild()
  : () => {
      const watcher = watch(watchOptions.watch, {
        ignoreInitial: true,
        ignored: watchOptions.ignore,
      });
      watcher.on('ready', () => {
        debug('ready to watch for file changes');
        logger.alert('[Watcher]: Watching for file changes\n');
        initialBuild();
        watcher
          .on('change', (path) => {
            restartOnChange(`${path} was changed`);
          })
          .on('error', (error) => {
            debug(`watcher error - ${error}`);
            console.log(`error - ${error}`);
          });
      });
    };