Fixed bug where calling scan multiple times adds multiple discovery events, closes #10

package.json

@@ -1,6 +1,6 @@
 {
   "name": "node-poweredup",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "description": "A Node.js module to interface with LEGO Powered UP components.",
   "homepage": "https://github.com/nathankellenicki/node-poweredup/",
   "main": "dist/index.js",

src/lpf2hub.ts

@@ -240,7 +240,7 @@ export class LPF2Hub extends Hub {
 
         if ((data[3] === 0x3b && this.type === Consts.HubType.POWERED_UP_REMOTE) || (data[3] === 0x3c && this.type !== Consts.HubType.POWERED_UP_REMOTE)) { // Voltage
             data = this._padMessage(data, 6);
-            const batteryLevel = (data.readUInt16LE(4) / 4096) * 100;
+            const batteryLevel = data.readUInt16LE(4) / 400;
             this._batteryLevel = Math.floor(batteryLevel);
             return;
         } else if (data[3] === 0x3b && this.type !== Consts.HubType.POWERED_UP_REMOTE) { // Current (Non-PUP Remote)

src/poweredup.ts

@@ -19,6 +19,7 @@ import noble = require("noble-mac");
 
 let ready = false;
 let wantScan = false;
+let discoveryEventAttached = false;
 
 const startScanning = () => {
     if (isBrowserContext) {
@@ -55,6 +56,7 @@ export class PoweredUP extends EventEmitter {
 
     constructor () {
         super();
+        this._discoveryEventHandler = this._discoveryEventHandler.bind(this);
     }
 
 
@@ -65,7 +67,56 @@ export class PoweredUP extends EventEmitter {
     public scan () {
         wantScan = true;
 
-        noble.on("discover", async (peripheral: Peripheral) => {
+        if (!discoveryEventAttached) {
+            noble.on("discover", this._discoveryEventHandler);
+            discoveryEventAttached = true;
+        }
+
+        if (ready) {
+            debug("Scanning started");
+            startScanning();
+        }
+    }
+
+
+    /**
+     * Stop scanning for Powered UP Hub devices.
+     * @method PoweredUP#stop
+     */
+    public stop () {
+        wantScan = false;
+
+        if (discoveryEventAttached) {
+            noble.removeListener("discover", this._discoveryEventHandler);
+            discoveryEventAttached = false;
+        }
+
+        noble.stopScanning();
+    }
+
+
+    /**
+     * Retrieve a Powered UP Hub by UUID.
+     * @method PoweredUP#getConnectedHubByUUID
+     * @param {string} uuid
+     * @returns {Hub | null}
+     */
+    public getConnectedHubByUUID (uuid: string) {
+        return this._connectedHubs[uuid];
+    }
+
+
+    /**
+     * Retrieve a list of Powered UP Hubs.
+     * @method PoweredUP#getConnectedHubs
+     * @returns {Hub[]}
+     */
+    public getConnectedHubs () {
+        return Object.keys(this._connectedHubs).map((uuid) => this._connectedHubs[uuid]);
+    }
+
+
+    private async _discoveryEventHandler (peripheral: Peripheral) {
 
         let hub: Hub;
 
@@ -111,43 +162,6 @@ export class PoweredUP extends EventEmitter {
          */
         this.emit("discover", hub);
 
-        });
-
-        if (ready) {
-            debug("Scanning started");
-            startScanning();
-        }
-    }
-
-
-    /**
-     * Stop scanning for Powered UP Hub devices.
-     * @method PoweredUP#stop
-     */
-    public stop () {
-        wantScan = false;
-        noble.stopScanning();
-    }
-
-
-    /**
-     * Retrieve a Powered UP Hub by UUID.
-     * @method PoweredUP#getConnectedHubByUUID
-     * @param {string} uuid
-     * @returns {Hub | null}
-     */
-    public getConnectedHubByUUID (uuid: string) {
-        return this._connectedHubs[uuid];
-    }
-
-
-    /**
-     * Retrieve a list of Powered UP Hubs.
-     * @method PoweredUP#getConnectedHubs
-     * @returns {Hub[]}
-     */
-    public getConnectedHubs () {
-        return Object.keys(this._connectedHubs).map((uuid) => this._connectedHubs[uuid]);
 }