add graceful_ipc option like in node-dev package

bin/ts-node-dev

@@ -54,7 +54,8 @@ var opts = minimist(devArgs, {
     'interval',
     'debounce',
     'watch',
-    'restart-terminated'
+    'restart-terminated',
+    'graceful_ipc'
   ],
   alias: {
     transpileOnly: 'T',

lib/index.js

@@ -174,6 +174,11 @@ module.exports = function(script, scriptArgs, nodeArgs, opts) {
     })
     compiler.writeReadyFile()
   }
+  const sendGracefulIPC = (graceful_ipc) => {
+    if (!child) return
+    log.debug(`Sending "${graceful_ipc}" ipc message to child`)
+    child.send(graceful_ipc);
+  }
   const killChild = () => {
     if (!child) return
     log.debug('Sending SIGTERM kill to child pid', child.pid)
@@ -191,11 +196,15 @@ module.exports = function(script, scriptArgs, nodeArgs, opts) {
     child.stopping = true
     child.respawn = true
     if (child.connected === undefined || child.connected === true) {
-      log.debug('Disconnecting from child')
-      child.disconnect()
-      //if (!willTerminate) {
-        killChild()
-      //}
+      if(opts.graceful_ipc){
+        sendGracefulIPC(opts.graceful_ipc)
+      } else {
+        log.debug('Disconnecting from child')
+        child.disconnect()
+        //if (!willTerminate) {
+          killChild()
+        //}
+      }
     }
   }
 
@@ -237,7 +246,11 @@ module.exports = function(script, scriptArgs, nodeArgs, opts) {
   // Relay SIGTERM
   process.on('SIGTERM', function() {
     log.debug('Process got SIGTERM')
-    killChild()
+    if(opts.graceful_ipc){
+      sendGracefulIPC(opts.graceful_ipc)
+    } else {
+      killChild()
+    }
     if (opts['restart-terminated']) {
       var timeout = opts['restart-terminated'] || 0
       log.info('Restarting terminated in ' + timeout + ' seconds')

test/fixture/graceful-ipc.ts

@@ -0,0 +1,7 @@
+console.log('v1')
+
+process.on('message', function(m) {
+  console.log(m);
+  process.disconnect();
+  process.exit();
+})

test/index.ts

@@ -172,3 +172,19 @@ test('It allows use custom TS Transformers', async (t) => {
   await ps.waitForLine(/transformed/)
   await ps.exit()
 })
+
+// TODO: fix --graceful_ipc option won't work with spawnTsNodeDev()
+// p.s the option works when manually running node on the terminal like this:
+// node .\bin\ts-node-dev --graceful_ipc=AWESOME .\test\fixture\graceful-ipc.ts
+test.skip('It send IPC message during restart events', async (t) => {
+  const ps = spawnTsNodeDev('--graceful_ipc="GRACETERM" graceful-ipc.ts')
+
+  // changing the file to trigger restart
+  setTimeout(() => replaceText('graceful-ipc.ts', 'v1', 'v2'), 250)
+
+  await ps.waitForLine(/GRACETERM/)
+
+  await ps.exit()
+
+  replaceText('graceful-ipc.ts', 'v2', 'v1')
+})