Refactor code + add auto-retry

src/app/icons.tsx

@@ -0,0 +1,80 @@
+"use client";
+import React from "react";
+
+export function SpeakerOnIcon() {
+  return (
+    <svg
+      xmlns="http://www.w3.org/2000/svg"
+      fill="none"
+      viewBox="0 0 24 24"
+      strokeWidth={1.5}
+      stroke="currentColor"
+      className="w-6 h-6"
+    >
+      <path
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        d="M19.114 5.636a9 9 0 010 12.728M16.463 8.288a5.25 5.25 0 010 7.424M6.75 8.25l4.72-4.72a.75.75 0 011.28.53v15.88a.75.75 0 01-1.28.53l-4.72-4.72H4.51c-.88 0-1.704-.507-1.938-1.354A9.01 9.01 0 012.25 12c0-.83.112-1.633.322-2.396C2.806 8.756 3.63 8.25 4.51 8.25H6.75z"
+      />
+    </svg>
+  );
+}
+export function SpeakerOffIcon() {
+  return (
+    <svg
+      xmlns="http://www.w3.org/2000/svg"
+      fill="none"
+      viewBox="0 0 24 24"
+      strokeWidth={1.5}
+      stroke="currentColor"
+      className="w-6 h-6"
+    >
+      <path
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        d="M17.25 9.75L19.5 12m0 0l2.25 2.25M19.5 12l2.25-2.25M19.5 12l-2.25 2.25m-10.5-6l4.72-4.72a.75.75 0 011.28.531V19.94a.75.75 0 01-1.28.53l-4.72-4.72H4.51c-.88 0-1.704-.506-1.938-1.354A9.01 9.01 0 012.25 12c0-.83.112-1.633.322-2.395C2.806 8.757 3.63 8.25 4.51 8.25H6.75z"
+      />
+    </svg>
+  );
+}
+export function EyeIcon() {
+  return (
+    <svg
+      xmlns="http://www.w3.org/2000/svg"
+      fill="none"
+      viewBox="0 0 24 24"
+      strokeWidth={1.5}
+      stroke="currentColor"
+      className="w-6 h-6"
+    >
+      <path
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        d="M2.036 12.322a1.012 1.012 0 010-.639C3.423 7.51 7.36 4.5 12 4.5c4.638 0 8.573 3.007 9.963 7.178.07.207.07.431 0 .639C20.577 16.49 16.64 19.5 12 19.5c-4.638 0-8.573-3.007-9.963-7.178z"
+      />
+      <path
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        d="M15 12a3 3 0 11-6 0 3 3 0 016 0z"
+      />
+    </svg>
+  );
+}
+export function MegaphoneIcon() {
+  return (
+    <svg
+      xmlns="http://www.w3.org/2000/svg"
+      fill="none"
+      viewBox="0 0 24 24"
+      strokeWidth={1.5}
+      stroke="currentColor"
+      className="w-6 h-6"
+    >
+      <path
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        d="M10.34 15.84c-.688-.06-1.386-.09-2.09-.09H7.5a4.5 4.5 0 110-9h.75c.704 0 1.402-.03 2.09-.09m0 9.18c.253.962.584 1.892.985 2.783.247.55.06 1.21-.463 1.511l-.657.38c-.551.318-1.26.117-1.527-.461a20.845 20.845 0 01-1.44-4.282m3.102.069a18.03 18.03 0 01-.59-4.59c0-1.586.205-3.124.59-4.59m0 9.18a23.848 23.848 0 018.835 2.535M10.34 6.66a23.847 23.847 0 008.835-2.535m0 0A23.74 23.74 0 0018.795 3m.38 1.125a23.91 23.91 0 011.014 5.395m-1.014 8.855c-.118.38-.245.754-.38 1.125m.38-1.125a23.91 23.91 0 001.014-5.395m0-3.46c.495.413.811 1.035.811 1.73 0 .695-.316 1.317-.811 1.73m0-3.46a24.347 24.347 0 010 3.46"
+      />
+    </svg>
+  );
+}

src/app/page.tsx

@@ -1,114 +1,96 @@
 "use client";
 
-import React from "react";
+import React, { useCallback, useMemo } from "react";
 import Image from "next/image";
-import {
-  TParsedDMMResponse,
-  debounceReadingFunc,
-  parseDMMBuffer,
-  startBluetoothCoonection as startBluetoothConnection,
-} from "@/helpers/parseDMM";
+import { TParsedDMMResponse, parseDMMBuffer } from "@/helpers/parseDMM";
+import { debounceReadingFunc } from "@/helpers/debounce";
+import { BluetoothConnection } from "@/helpers/bluetooth";
 import { startBuzz } from "@/helpers/buzzSound";
-import {
-  MutableRefObject,
-  useEffect,
-  useRef,
-  useState,
-  Dispatch,
-  SetStateAction,
-} from "react";
+import { useEffect, useRef, useState } from "react";
+import { EyeIcon, MegaphoneIcon, SpeakerOnIcon, SpeakerOffIcon } from "./icons";
+import { useStateWithRef } from "@/helpers/custom-hooks";
 
-function SpeakerOnIcon() {
-  return (
-    <svg
-      xmlns="http://www.w3.org/2000/svg"
-      fill="none"
-      viewBox="0 0 24 24"
-      strokeWidth={1.5}
-      stroke="currentColor"
-      className="w-6 h-6"
-    >
-      <path
-        strokeLinecap="round"
-        strokeLinejoin="round"
-        d="M19.114 5.636a9 9 0 010 12.728M16.463 8.288a5.25 5.25 0 010 7.424M6.75 8.25l4.72-4.72a.75.75 0 011.28.53v15.88a.75.75 0 01-1.28.53l-4.72-4.72H4.51c-.88 0-1.704-.507-1.938-1.354A9.01 9.01 0 012.25 12c0-.83.112-1.633.322-2.396C2.806 8.756 3.63 8.25 4.51 8.25H6.75z"
-      />
-    </svg>
-  );
+function useBluetoothConnection() {
+  let bluetoothConnectionRef = useRef<BluetoothConnection | null>(null);
+  if (bluetoothConnectionRef.current == null) {
+    bluetoothConnectionRef.current = new BluetoothConnection();
+  }
+  const bluetoothConnection = bluetoothConnectionRef.current;
+  const {
+    startConnection,
+    startAutoReconnect,
+    addConnectHandler,
+    addDisconnectHandler,
+    addNotifyHandler,
+    disconnect,
+    enableShouldAutoReconnect,
+    disableShouldAutoReconnect,
+  } = bluetoothConnection;
+  return {
+    startConnection,
+    startAutoReconnect,
+    addConnectHandler,
+    addDisconnectHandler,
+    addNotifyHandler,
+    disconnect,
+    enableShouldAutoReconnect,
+    disableShouldAutoReconnect,
+  };
 }
 
-function SpeakerOffIcon() {
-  return (
-    <svg
-      xmlns="http://www.w3.org/2000/svg"
-      fill="none"
-      viewBox="0 0 24 24"
-      strokeWidth={1.5}
-      stroke="currentColor"
-      className="w-6 h-6"
-    >
-      <path
-        strokeLinecap="round"
-        strokeLinejoin="round"
-        d="M17.25 9.75L19.5 12m0 0l2.25 2.25M19.5 12l2.25-2.25M19.5 12l-2.25 2.25m-10.5-6l4.72-4.72a.75.75 0 011.28.531V19.94a.75.75 0 01-1.28.53l-4.72-4.72H4.51c-.88 0-1.704-.506-1.938-1.354A9.01 9.01 0 012.25 12c0-.83.112-1.633.322-2.395C2.806 8.757 3.63 8.25 4.51 8.25H6.75z"
-      />
-    </svg>
+function useSpeechApi() {
+  const [isMute, setIsMute, isMuteRef] = useStateWithRef<boolean>(false);
+  let [selectedVoiceURI, setSelectedVoiceURI, selectedVoiceURIRef] =
+    useStateWithRef<string | undefined>(undefined);
+  let [allVoices, setAllVoices, allVoicesRef] = useStateWithRef<
+    SpeechSynthesisVoice[] | undefined
+  >(undefined);
+
+  const speak = useCallback(
+    function speak(value: string) {
+      let speech = new SpeechSynthesisUtterance();
+      speech.lang = "en";
+      speech.text = value;
+      speech.voice =
+        allVoicesRef.current?.find(
+          ({ voiceURI }) => voiceURI == selectedVoiceURIRef.current,
+        ) || null;
+      speech.volume = isMuteRef.current ? 0 : 1;
+      window.speechSynthesis.speak(speech);
+    },
+    [isMuteRef, selectedVoiceURIRef, allVoicesRef],
   );
+
+  // Effect - Init all voices
+  useEffect(() => {
+    function _updateAllVoices() {
+      // Get List of Voices
+      const tempAllVoices = window.speechSynthesis.getVoices();
+      const allEnglishVoices = tempAllVoices.filter(({ lang }) =>
+        lang.startsWith("en"),
+      );
+      setAllVoices(allEnglishVoices);
+
+      if (allEnglishVoices.length > 0) {
+        // Initially set the First Voice in the Array.
+        setSelectedVoiceURI(allEnglishVoices[0].voiceURI);
+      }
     }
 
-function EyeIcon() {
-  return (
-    <svg
-      xmlns="http://www.w3.org/2000/svg"
-      fill="none"
-      viewBox="0 0 24 24"
-      strokeWidth={1.5}
-      stroke="currentColor"
-      className="w-6 h-6"
-    >
-      <path
-        strokeLinecap="round"
-        strokeLinejoin="round"
-        d="M2.036 12.322a1.012 1.012 0 010-.639C3.423 7.51 7.36 4.5 12 4.5c4.638 0 8.573 3.007 9.963 7.178.07.207.07.431 0 .639C20.577 16.49 16.64 19.5 12 19.5c-4.638 0-8.573-3.007-9.963-7.178z"
-      />
-      <path
-        strokeLinecap="round"
-        strokeLinejoin="round"
-        d="M15 12a3 3 0 11-6 0 3 3 0 016 0z"
-      />
-    </svg>
-  );
-}
+    _updateAllVoices();
+    window.speechSynthesis.onvoiceschanged = () => {
+      _updateAllVoices();
+    };
+  }, [setSelectedVoiceURI, setAllVoices]);
 
-function MegaphoneIcon() {
-  return (
-    <svg
-      xmlns="http://www.w3.org/2000/svg"
-      fill="none"
-      viewBox="0 0 24 24"
-      strokeWidth={1.5}
-      stroke="currentColor"
-      className="w-6 h-6"
-    >
-      <path
-        strokeLinecap="round"
-        strokeLinejoin="round"
-        d="M10.34 15.84c-.688-.06-1.386-.09-2.09-.09H7.5a4.5 4.5 0 110-9h.75c.704 0 1.402-.03 2.09-.09m0 9.18c.253.962.584 1.892.985 2.783.247.55.06 1.21-.463 1.511l-.657.38c-.551.318-1.26.117-1.527-.461a20.845 20.845 0 01-1.44-4.282m3.102.069a18.03 18.03 0 01-.59-4.59c0-1.586.205-3.124.59-4.59m0 9.18a23.848 23.848 0 018.835 2.535M10.34 6.66a23.847 23.847 0 008.835-2.535m0 0A23.74 23.74 0 0018.795 3m.38 1.125a23.91 23.91 0 011.014 5.395m-1.014 8.855c-.118.38-.245.754-.38 1.125m.38-1.125a23.91 23.91 0 001.014-5.395m0-3.46c.495.413.811 1.035.811 1.73 0 .695-.316 1.317-.811 1.73m0-3.46a24.347 24.347 0 010 3.46"
-      />
-    </svg>
-  );
-}
-
-function useBuzzSound() {}
-
-function useStateWithRef<TState>(
-  initialValue: TState,
-): [TState, Dispatch<SetStateAction<TState>>, MutableRefObject<TState>] {
-  const [value, setValue] = useState<TState>(initialValue);
-  const valueRef = useRef<TState>(initialValue);
-  valueRef.current = value;
-
-  return [value, setValue, valueRef];
+  return {
+    allVoices,
+    selectedVoiceURI,
+    setSelectedVoiceURI,
+    isMute,
+    setIsMute,
+    speak,
+  };
 }
 
 export default function Home() {
@@ -116,57 +98,45 @@ export default function Home() {
     undefined,
   );
   const [liveValue, setLiveValue] = useState<string | undefined>(undefined);
-  const [isMute, setIsMute, isMuteRef] = useStateWithRef<boolean>(false);
   const stopBuzzRef = useRef<(() => void) | undefined>(undefined);
 
-  let [selectedVoice, setSelectedVoice, selectedVoiceRef] = useStateWithRef<
-    string | undefined
-  >(undefined);
-  let [allVoices, setAllVoices] = useState<SpeechSynthesisVoice[]>();
-  let multimeterBluetoothDeviceRef = useRef<BluetoothDevice | undefined>(
-    undefined,
-  );
-  let multimeterDisconnectRef = useRef<(() => void) | undefined>(undefined);
-
   const [showDisconnect, setShowDisconnect] = useState(false);
   const showConnect = !showDisconnect;
 
-  function resetStatusAfterDisconnect() {
-    if (multimeterBluetoothDeviceRef.current !== undefined) {
-      // Only announce once
-      speak("Multimeter disconnected");
-    }
-    multimeterBluetoothDeviceRef.current = undefined;
-    multimeterDisconnectRef.current = undefined;
-    setLiveValue(undefined);
-    setPrintedValue(undefined);
-    setShowDisconnect(false);
-  }
+  const {
+    startConnection,
+    startAutoReconnect,
+    addConnectHandler,
+    addDisconnectHandler,
+    addNotifyHandler,
+    disconnect,
+    enableShouldAutoReconnect,
+    disableShouldAutoReconnect,
+  } = useBluetoothConnection();
+  const {
+    allVoices,
+    selectedVoiceURI,
+    setSelectedVoiceURI,
+    isMute,
+    setIsMute,
+    speak,
+  } = useSpeechApi();
 
-  function speak(value: string) {
-    let speech = new SpeechSynthesisUtterance();
-    speech.lang = "en";
-    speech.text = value;
-    speech.voice =
-      allVoices?.find(
-        ({ voiceURI }) => voiceURI === selectedVoiceRef.current,
-      ) || null;
-    speech.volume = isMuteRef.current ? 0 : 1;
-    window.speechSynthesis.speak(speech);
-  }
-
-  function handleConnectClick() {
-    const debouncedLogAndSpeak = debounceReadingFunc((value) => {
+  const debouncedLogAndSpeak = useMemo(
+    () =>
+      debounceReadingFunc((value) => {
         value = value as string;
         setPrintedValue(value);
         console.log(value);
         speak(value.replace("-", "Minus "));
-    }, 700);
+      }, 700),
+    [speak],
+  );
 
   function handleBuzz(parsedDMMresponse: TParsedDMMResponse) {
     const { isBuzz, isDiode } = parsedDMMresponse;
     // If BUZZ sign & not DIODE sign & not mute
-      if (isBuzz && !isDiode && !isMuteRef.current) {
+    if (isBuzz && !isDiode && !isMute) {
       // Multimeter is buzzing, reciprocate
       const { stop } = startBuzz();
       stopBuzzRef.current = stop;
@@ -187,48 +157,37 @@ export default function Home() {
     // Buzz, if needed
     handleBuzz(parsedDMMresponse);
   }
-    startBluetoothConnection({
-      onDisconnect: () => resetStatusAfterDisconnect(),
-      onNotify,
-    }).then((obj) => {
-      multimeterBluetoothDeviceRef.current = obj.multimeterBluetoothDevice;
-      multimeterDisconnectRef.current = obj.disconnect;
+  addNotifyHandler(onNotify);
+
+  function onDisconnect() {
+    speak("Multimeter disconnected");
+
+    setLiveValue(undefined);
+    setPrintedValue(undefined);
+    setShowDisconnect(false);
+
+    // Has internal check for shouldAutoReconnect
+    startAutoReconnect();
+  }
+  addDisconnectHandler(onDisconnect);
+
+  function onConnect() {
+    // TODO: Check if autoReconnect settings enabled
+    enableShouldAutoReconnect();
     setShowDisconnect(true);
     speak("Connected");
-    });
+  }
+  addConnectHandler(onConnect);
+
+  function handleConnectClick() {
+    startConnection();
   }
 
   function handleDisconnectClick() {
-    if (multimeterDisconnectRef.current) {
-      console.log("Calling disconnect...");
-      multimeterDisconnectRef.current();
-
-      resetStatusAfterDisconnect();
-    } else {
-      console.log("Disconnect is not set");
+    console.log("Clicked disconnect");
+    disableShouldAutoReconnect();
+    disconnect();
   }
-  }
-
-  useEffect(() => {
-    function _updateAllVoices() {
-      // Get List of Voices
-      const tempAllVoices = window.speechSynthesis.getVoices();
-      const allEnglishVoices = tempAllVoices.filter(({ lang }) =>
-        lang.startsWith("en"),
-      );
-      setAllVoices(allEnglishVoices);
-
-      if (allEnglishVoices.length > 0) {
-        // Initially set the First Voice in the Array.
-        setSelectedVoice(allEnglishVoices[0].name);
-      }
-    }
-
-    _updateAllVoices();
-    window.speechSynthesis.onvoiceschanged = () => {
-      _updateAllVoices();
-    };
-  }, [setSelectedVoice]);
 
   function handleMuteClick() {
     setIsMute(true);
@@ -294,8 +253,8 @@ export default function Home() {
           <select
             name="voice"
             className="mx-2 px-1 border-gray-200 border-2 border-solid rounded-sm bg-white text-black dark:bg-black dark:text-white"
-            value={selectedVoice}
-            onChange={(e) => setSelectedVoice(e.target.value)}
+            value={selectedVoiceURI}
+            onChange={(e) => setSelectedVoiceURI(e.target.value)}
           >
             {allVoices?.map(({ name, voiceURI }) => (
               <option key={voiceURI} value={voiceURI}>

src/helpers/bluetooth.ts

@@ -0,0 +1,168 @@
+import {
+  DEFAULT_CHARACTERISTIC_UUID,
+  DEFAULT_SERVICE_UUID,
+  AUTO_RECONNECT_INTERVAL_MS,
+} from "./constants";
+import { MultimeterError } from "./custom-error";
+
+export class BluetoothConnection {
+  multimeterBluetoothDevice: BluetoothDevice | null = null;
+  serviceUUID: string;
+  characteristicUUID: string;
+  gatt?: BluetoothRemoteGATTServer = undefined;
+  service?: BluetoothRemoteGATTService = undefined;
+  characteristic?: BluetoothRemoteGATTCharacteristic = undefined;
+  onNotifyExternal?: (bufferAsArray: number[]) => void = undefined;
+  onConnectExternal?: () => void = undefined;
+  onDisconnectExternal?: () => void = undefined;
+  autoReconnectTimer?: ReturnType<typeof setTimeout>;
+  shouldAutoReconnect = true;
+
+  constructor({
+    serviceUUID = DEFAULT_SERVICE_UUID,
+    characteristicUUID = DEFAULT_CHARACTERISTIC_UUID,
+  } = {}) {
+    this.serviceUUID = serviceUUID;
+    this.characteristicUUID = characteristicUUID;
+
+    // Bind methods
+    this.startConnection = this.startConnection.bind(this);
+    this.startAutoReconnect = this.startAutoReconnect.bind(this);
+    this.addConnectHandler = this.addConnectHandler.bind(this);
+    this.addDisconnectHandler = this.addDisconnectHandler.bind(this);
+    this.addNotifyHandler = this.addNotifyHandler.bind(this);
+    this.disconnect = this.disconnect.bind(this);
+    this.enableShouldAutoReconnect = this.enableShouldAutoReconnect.bind(this);
+    this.disableShouldAutoReconnect =
+      this.disableShouldAutoReconnect.bind(this);
+    this._onConnect = this._onConnect.bind(this);
+    this._onNotify = this._onNotify.bind(this);
+    this._onDisconnect = this._onDisconnect.bind(this);
+  }
+
+  async startConnection() {
+    this.multimeterBluetoothDevice = await this.requestBluetoothDevice();
+    this.multimeterBluetoothDevice.removeEventListener(
+      "gattserverdisconnected",
+      this._onDisconnect,
+    );
+    this.multimeterBluetoothDevice.addEventListener(
+      "gattserverdisconnected",
+      this._onDisconnect,
+    );
+    this.connectGatt();
+  }
+
+  async autoReconnect() {
+    await this.connectGatt();
+  }
+
+  async requestBluetoothDevice() {
+    const tmpBluetoothDevice = await navigator.bluetooth.requestDevice({
+      filters: [
+        {
+          services: [this.serviceUUID],
+        },
+      ],
+    });
+    if (tmpBluetoothDevice === undefined) {
+      throw new MultimeterError("Multimeter not selected");
+    }
+    return tmpBluetoothDevice;
+  }
+
+  async connectGatt() {
+    if (this.multimeterBluetoothDevice == null) {
+      throw new MultimeterError("multimeterBluetoothDevice is not populated");
+    }
+    if (this.multimeterBluetoothDevice.gatt === undefined) {
+      throw new MultimeterError("BLE: Gatt is not available");
+    }
+
+    this.gatt = await this.multimeterBluetoothDevice.gatt.connect();
+    this.service = await this.gatt.getPrimaryService(this.serviceUUID);
+    this.characteristic = await this.service.getCharacteristic(
+      this.characteristicUUID,
+    );
+    if (this.characteristic.properties.notify) {
+      this.characteristic.removeEventListener(
+        "characteristicvaluechanged",
+        this._onNotify,
+      );
+      this.characteristic.addEventListener(
+        "characteristicvaluechanged",
+        this._onNotify,
+      );
+      await this.characteristic.startNotifications();
+    }
+
+    this._onConnect();
+  }
+
+  async _onConnect() {
+    this.onConnectExternal?.();
+  }
+
+  async _onNotify() {
+    const buffer: ArrayBuffer | undefined = this.characteristic?.value?.buffer;
+    if (buffer == undefined) {
+      throw new MultimeterError("BLE: Notify buffer is undefined");
+    }
+    const bufferAsArray = [...new Uint8Array(buffer)];
+    this.onNotifyExternal?.(bufferAsArray);
+  }
+
+  async _onDisconnect() {
+    console.log("Multimeter disconnected");
+    this.characteristic?.removeEventListener(
+      "characteristicvaluechanged",
+      this._onNotify,
+    );
+
+    this.onDisconnectExternal?.();
+  }
+
+  startAutoReconnect() {
+    // Stop, if already running
+    this.stopAutoReconnect();
+    if (this.multimeterBluetoothDevice !== null && this.shouldAutoReconnect) {
+      this.autoReconnectTimer = setTimeout(async () => {
+        try {
+          await this.autoReconnect();
+        } catch (_err) {
+          this.startAutoReconnect();
+        }
+      }, AUTO_RECONNECT_INTERVAL_MS);
+    } else {
+      this.autoReconnectTimer = undefined;
+    }
+  }
+  stopAutoReconnect() {
+    clearTimeout(this.autoReconnectTimer);
+    this.autoReconnectTimer = undefined;
+  }
+
+  addNotifyHandler(handler: (bufferAsArray: number[]) => void) {
+    this.onNotifyExternal = handler;
+  }
+
+  addConnectHandler(handler: () => void) {
+    this.onConnectExternal = handler;
+  }
+
+  addDisconnectHandler(handler: () => void) {
+    this.onDisconnectExternal = handler;
+  }
+
+  disconnect() {
+    this.gatt?.disconnect();
+  }
+
+  enableShouldAutoReconnect() {
+    this.shouldAutoReconnect = true;
+  }
+
+  disableShouldAutoReconnect() {
+    this.shouldAutoReconnect = false;
+  }
+}

src/helpers/constants.ts

@@ -78,3 +78,5 @@ export const LCD_SYMBOL_BIT_POSITION_MAP = {
 };
 
 export type KNOWN_SYMBOLS = keyof typeof LCD_SYMBOL_BIT_POSITION_MAP;
+
+export const AUTO_RECONNECT_INTERVAL_MS = 5000;

src/helpers/custom-error.ts

@@ -0,0 +1 @@
+export class MultimeterError extends Error {}

src/helpers/custom-hooks.ts

@@ -0,0 +1,17 @@
+import {
+  MutableRefObject,
+  useRef,
+  useState,
+  Dispatch,
+  SetStateAction,
+} from "react";
+
+export function useStateWithRef<TState>(
+  initialValue: TState,
+): [TState, Dispatch<SetStateAction<TState>>, MutableRefObject<TState>] {
+  const [value, setValue] = useState<TState>(initialValue);
+  const valueRef = useRef<TState>(initialValue);
+  valueRef.current = value;
+
+  return [value, setValue, valueRef];
+}

src/helpers/debounce.ts

@@ -0,0 +1,27 @@
+export function debounceReadingFunc(
+  callbackFn: (input: string | number) => void,
+  debounceMillis = 1000,
+) {
+  let timerId: ReturnType<typeof setTimeout> | undefined = undefined;
+  let lastReturnedValue: number | string | undefined = undefined;
+  let lastNewValue: number | string | undefined = undefined;
+
+  return function debouncedReading(newValue: string | number | undefined) {
+    if (newValue !== undefined && newValue !== lastNewValue) {
+      if (timerId !== undefined) {
+        clearTimeout(timerId);
+        timerId = undefined;
+      }
+
+      if (newValue !== lastReturnedValue) {
+        timerId = setTimeout(() => {
+          lastReturnedValue = newValue;
+          timerId = undefined;
+
+          callbackFn(newValue);
+        }, debounceMillis);
+      }
+    }
+    lastNewValue = newValue;
+  };
+}

src/helpers/parseDMM.ts

@@ -1,7 +1,5 @@
 import {
   CHAR_MAP,
-  DEFAULT_CHARACTERISTIC_UUID,
-  DEFAULT_SERVICE_UUID,
   KNOWN_CHARS,
   KNOWN_UNKNOWN_CHARS,
   LCD_CHAR_BIT_POSITIONS,
@@ -222,105 +220,6 @@ export function parseDMMBuffer(bufferAsNumberArray: number[]) {
 
 export type TParsedDMMResponse = ReturnType<typeof parseDMMBuffer>;
 
-class MultimeterError extends Error {}
-
-export async function startBluetoothCoonection({
-  serviceUUID = DEFAULT_SERVICE_UUID,
-  characteristicUUID = DEFAULT_CHARACTERISTIC_UUID,
-  onNotify = printBLENotify,
-  onDisconnect = () => {},
-} = {}) {
-  let multimeterBluetoothDevice: BluetoothDevice | null = null;
-  multimeterBluetoothDevice = await navigator.bluetooth.requestDevice({
-    filters: [
-      {
-        services: [serviceUUID],
-      },
-    ],
-  });
-  if (multimeterBluetoothDevice === undefined) {
-    throw new MultimeterError("Multimeter not selected");
-  }
-  if (multimeterBluetoothDevice.gatt === undefined) {
-    throw new MultimeterError("BLE: Gatt is not available");
-  }
-  let gatt = await multimeterBluetoothDevice.gatt.connect();
-  multimeterBluetoothDevice.addEventListener("gattserverdisconnected", (ev) => {
-    console.log("Multimeter disconnected");
-    onDisconnect();
-  });
-
-  let service = await gatt.getPrimaryService(serviceUUID);
-  let characteristic = await service.getCharacteristic(characteristicUUID);
-
-  async function notifyCallback() {
-    const buffer: ArrayBuffer | undefined = characteristic.value?.buffer;
-    if (buffer == undefined) {
-      throw new MultimeterError("BLE: Notify buffer is undefined");
-    }
-    const bufferAsArray = [...new Uint8Array(buffer)];
-    onNotify(bufferAsArray);
-  }
-
-  if (characteristic.properties.notify) {
-    characteristic.addEventListener(
-      "characteristicvaluechanged",
-      notifyCallback,
-    );
-    await characteristic.startNotifications();
-  }
-
-  return {
-    multimeterBluetoothDevice,
-    service,
-    characteristic,
-    removeEventListener() {
-      characteristic.removeEventListener(
-        "characteristicvaluechanged",
-        notifyCallback,
-      );
-    },
-    disconnect() {
-      multimeterBluetoothDevice?.gatt?.disconnect();
-      onDisconnect();
-    },
-  };
-}
-
-const debouncedLog = debounceReadingFunc((value) => console.log(value));
-export function printBLENotify(bufferAsArray: number[]) {
-  const printValue = parseDMMBuffer(bufferAsArray).toString();
-  debouncedLog(printValue);
-}
-
-export function debounceReadingFunc(
-  callbackFn: (input: string | number) => void,
-  debounceMillis = 1000,
-) {
-  let timerId: ReturnType<typeof setTimeout> | undefined = undefined;
-  let lastReturnedValue: number | string | undefined = undefined;
-  let lastNewValue: number | string | undefined = undefined;
-
-  return function debouncedReading(newValue: string | number | undefined) {
-    if (newValue !== undefined && newValue !== lastNewValue) {
-      if (timerId !== undefined) {
-        clearTimeout(timerId);
-        timerId = undefined;
-      }
-
-      if (newValue !== lastReturnedValue) {
-        timerId = setTimeout(() => {
-          lastReturnedValue = newValue;
-          timerId = undefined;
-
-          callbackFn(newValue);
-        }, debounceMillis);
-      }
-    }
-    lastNewValue = newValue;
-  };
-}
-
 export function readCharacter(
   binString: string,
   charIndex: number,