added nodejs-samples folder: test2

esp32-nodejs-samples @ a0048ac1

-Subproject commit a0048ac138a3a29330c7d935faa03dd6625a1b49

listen-notification.js

+'use strict'
+
+const noble = require('noble')
+
+noble.on('stateChange', state => {
+  console.log('state change', state)
+  if (state === 'poweredOn') {
+    noble.startScanning()
+  } else {
+    noble.stopScanning()
+  }
+})
+
+noble.on('discover', peri => {
+  noble.stopScanning()
+  const ad = peri.advertisement
+  console.log("ad name: ", ad.localName)
+  if (ad.localName == "ESP_GATTS_SWITCH") {
+    console.log("found target esp")
+    peri.connect(error => {
+      console.log("conected")
+      if (error) {
+        console.log("connection error:", error)
+      }
+      peri.discoverServices([], (error, services) => {
+        if (error) {
+          console.log("discover service error", error)
+        }
+        services.forEach(service => {
+          console.log("service uuid: ", service.uuid)
+          if (service.uuid == "ff") {
+            console.log("ff")
+            service.discoverCharacteristics([], (error, charas) => {
+              if (error) {
+                console.log("discover characteristics error", error)
+              }
+              charas.forEach(chara => {
+                console.log("found chara: ", chara.uuid)
+                if (chara.uuid == "ff01") {
+                  chara.notify(true, (error) => {
+                    if (error) {
+                      console.log('listen notif error', error)
+                    } else {
+                      console.log('listen notif')
+                    }
+                  })
+                  chara.on('data', (data, isNotif) => {
+                    console.log('receoved notif', data, isNotif)
+                  })
+                }
+              })
+            })
+          }
+        })
+      })
+    })
+  }
+})