diff --git a/app/client/components/PerformanceDashboard.js b/app/client/components/PerformanceDashboard.js
index e638cb1..b5b4dbe 100644
--- a/app/client/components/PerformanceDashboard.js
+++ b/app/client/components/PerformanceDashboard.js
@@ -28,7 +28,7 @@ export class PerformanceDashboard extends AppElement {
   render () {
     const metrics = this.calculateFormattedMetrics(this.appState.metrics)
     return html`
-      <dashboard-metric .icon=${icon_route} .unit=${metrics?.distanceTotal?.unit} .value=${metrics?.distanceTotal?.value}></dashboard-metric>
+      <dashboard-metric .icon=${icon_route} .unit=${metrics?.distanceTotal?.unit || 'm'} .value=${metrics?.distanceTotal?.value}></dashboard-metric>
       <dashboard-metric .icon=${icon_stopwatch} unit="/500m" .value=${metrics?.splitFormatted?.value}></dashboard-metric>
       <dashboard-metric .icon=${icon_bolt} unit="watt" .value=${metrics?.power?.value}></dashboard-metric>
       <dashboard-metric .icon=${icon_paddle} unit="/min" .value=${metrics?.strokesPerMinute?.value}></dashboard-metric>
diff --git a/app/client/index.js b/app/client/index.js
index 6a13fcf..54c58ae 100644
--- a/app/client/index.js
+++ b/app/client/index.js
@@ -36,7 +36,6 @@ export class App extends LitElement {
     })
 
     // notify the app about the triggered action
-    // todo: lets see if this solution sticks...
     this.addEventListener('triggerAction', (event) => {
       this.app.handleAction(event.detail)
     })
@@ -51,7 +50,7 @@ export class App extends LitElement {
 
   // return a deep copy of the state to other components to minimize risk of side effects
   getState = () => {
-    // todo: could use structuredClone once the browser support is wider
+    // could use structuredClone once the browser support is wider
     // https://developer.mozilla.org/en-US/docs/Web/API/structuredClone
     return JSON.parse(JSON.stringify(this.appState))
   }
diff --git a/app/client/lib/app.js b/app/client/lib/app.js
index 6f190f7..68ea480 100644
--- a/app/client/lib/app.js
+++ b/app/client/lib/app.js
@@ -6,6 +6,7 @@
 */
 
 import NoSleep from 'nosleep.js'
+import { filterObjectByKeys } from './helper'
 
 const rowingMetricsFields = ['strokesTotal', 'distanceTotal', 'caloriesTotal', 'power', 'heartrate',
   'heartrateBatteryLevel', 'splitFormatted', 'strokesPerMinute', 'durationTotalFormatted']
@@ -42,7 +43,7 @@ export function createApp (app) {
       }, 1000)
     })
 
-    // todo: we have to use different types of messages to make processing easier
+    // todo: we should use different types of messages to make processing easier
     socket.addEventListener('message', (event) => {
       try {
         const data = JSON.parse(event.data)
@@ -50,15 +51,10 @@ export function createApp (app) {
         let activeFields = rowingMetricsFields
         // if we are in reset state only update heart rate
         if (data.strokesTotal === 0) {
-          activeFields = ['heartrate']
+          activeFields = ['heartrate', 'heartrateBatteryLevel']
         }
 
-        const filteredData = Object.keys(data)
-          .filter(key => activeFields.includes(key))
-          .reduce((obj, key) => {
-            obj[key] = data[key]
-            return obj
-          }, {})
+        const filteredData = filterObjectByKeys(data, activeFields)
 
         let updatedState = { ...app.getState(), metrics: filteredData }
         if (data.peripheralMode) {
@@ -89,12 +85,7 @@ export function createApp (app) {
   function resetFields () {
     const appState = app.getState()
     // drop all metrics except heartrate
-    appState.metrics = Object.keys(appState.metrics)
-      .filter(key => key === 'heartrate' || key === 'heartrateBatteryLevel')
-      .reduce((obj, key) => {
-        obj[key] = appState.metrics[key]
-        return obj
-      }, {})
+    appState.metrics = filterObjectByKeys(appState.metrics, ['heartrate', 'heartrateBatteryLevel'])
     app.updateState(appState)
   }
 
diff --git a/app/client/lib/helper.js b/app/client/lib/helper.js
new file mode 100644
index 0000000..16bae13
--- /dev/null
+++ b/app/client/lib/helper.js
@@ -0,0 +1,16 @@
+'use strict'
+/*
+  Open Rowing Monitor, https://github.com/laberning/openrowingmonitor
+
+  Helper functions
+*/
+
+// Filters an object so that it only contains the attributes that are defined in a list
+export function filterObjectByKeys (object, keys) {
+  return Object.keys(object)
+    .filter(key => keys.includes(key))
+    .reduce((obj, key) => {
+      obj[key] = object[key]
+      return obj
+    }, {})
+}
diff --git a/app/client/lib/network.js b/app/client/lib/network.js
deleted file mode 100644
index bcca50f..0000000
--- a/app/client/lib/network.js
+++ /dev/null
@@ -1,5 +0,0 @@
-'use strict'
-/*
-  Open Rowing Monitor, https://github.com/laberning/openrowingmonitor
-
-*/