flow like the river

BACK_BACK/node_modules/@parcel/watcher/lib/child.js

@@ -0,0 +1,61 @@
+"use strict";
+
+const _require = require('chokidar'),
+      FSWatcher = _require.FSWatcher;
+
+const _require2 = require('@parcel/utils'),
+      errorUtils = _require2.errorUtils;
+
+const optionsTransfer = require('./options');
+
+let watcher;
+
+function sendEvent(event, path) {
+  process.send({
+    event: event,
+    path: path
+  });
+}
+
+function handleError(e) {
+  sendEvent('watcherError', errorUtils.errorToJson(e));
+}
+
+function init(options) {
+  options = optionsTransfer.decode(options);
+  watcher = new FSWatcher(options);
+  watcher.on('all', sendEvent);
+  sendEvent('ready');
+}
+
+function executeFunction(functionName, args) {
+  try {
+    watcher[functionName](...args);
+  } catch (e) {
+    handleError(e);
+  }
+}
+
+process.on('message', msg => {
+  switch (msg.type) {
+    case 'init':
+      init(msg.options);
+      break;
+
+    case 'function':
+      executeFunction(msg.name, msg.args);
+      break;
+
+    case 'die':
+      process.exit();
+      break;
+
+    case 'emulate_error':
+      throw new Error('this is an emulated error');
+  }
+});
+process.on('error', handleError);
+process.on('uncaughtException', handleError);
+process.on('disconnect', () => {
+  process.exit();
+});