how to auto reconnect bangle?

Bangle is so interesting, and I using it to get realtime emotional data(from HRM Sensor). but have some problems for stable connection. commonly after 3-5 minutes, bangles connection disconnected.
so I wanna make a code automatically reconnect with no popup window of BLE connection when it disconnected. can you help me?

What are you connecting to the Bangle from? What OS/what programming language?

If you're talking about Web Bluetooth then reconnection without a popup is possible, but the Puck.js library doesn't do that automatically. You could however just use Web Bluetooth directly. They even have a reconnect example at https://googlechrome.github.io/samples/web-bluetooth/automatic-reconnect.html

Hi Gordon! my OS is Window10, and programming language is Javascript.
I refer to this example, my frontend framework is Vue.js. I share some of codes of page.

   bangleCode: `Bangle.setLCDPower(1);
        Bangle.setLCDTimeout(0);
        Bangle.setHRMPower(1);
        var hrmInfo, hrmOffset = 0;
        var hrmInterval;
        var btm = g.getHeight()-1;
        
        function onHRM(h) {
          if (counter!==undefined) {
            // the first time we're called remove
            // the countdown
            counter = undefined;
            g.clear();
          }
          hrmInfo = h;
          /* On 2v09 and earlier firmwares the only solution for realtime
          HRM was to look at the 'raw' array that got reported. If you timed
          it right you could grab the data pretty much as soon as it was written.
          In new firmwares, '.raw' is not available. */
          if (hrmInterval) clearInterval(hrmInterval);
          hrmInterval = undefined;
          if (hrmInfo.raw) {
            hrmOffset = 0;
            setTimeout(function() {
              hrmInterval = setInterval(readHRM,41);
            }, 40);
          }
        
          var px = g.getWidth()/2;
          g.setFontAlign(0,0);
          g.clearRect(0,24,239,80);
          g.setFont("6x8").drawString("Confidence "+hrmInfo.confidence+"%", px, 75);
          var str = hrmInfo.bpm;
          g.setFontVector(40).drawString(str,px,45);
          px += g.stringWidth(str)/2;
          g.setFont("6x8");
          g.drawString("BPM",px+15,45);
        }
        Bangle.on('HRM', onHRM);
        /* On newer (2v10) firmwares we can subscribe to get
        HRM events as they happen */
        Bangle.on('HRM-raw', function(v) {
          hrmOffset++;
          if (hrmOffset>g.getWidth()) {
            hrmOffset=0;
            g.clearRect(0,80,239,239);
            g.moveTo(-100,0);
          }  
          y = E.clip(btm-v.filt/4,btm-10,btm);  
          g.setColor(1,0,0).fillRect(hrmOffset,btm, hrmOffset, y);
          y = E.clip(170 - (v.raw/2),80,btm);
          g.setColor(g.theme.fg).lineTo(hrmOffset, y);
          if (counter !==undefined) {
            counter = undefined;
            g.clear();
          }
        });
        
        // It takes 5 secs for us to get the first HRM event
        var counter = 5;
        function countDown() {
          if (counter) {
            g.drawString(counter--,g.getWidth()/2,g.getHeight()/2, true);
            setTimeout(countDown, 1000);
          }
        }
        g.clear().setFont("6x8",2).setFontAlign(0,0);
        g.drawString("Please wait...",g.getWidth()/2,g.getHeight()/2 - 16);
        countDown();        
        
        var wasHigh = 0, wasLow = 0;
        var lastHigh = getTime();
        var hrmList = [];
        var hrmInfo;
        
        function readHRM() {
          if (!hrmInfo) return;
        
          if (hrmOffset==0) {
            g.clearRect(0,100,239,239);
            g.moveTo(-100,0);
          }
          for (var i=0;i<2;i++) {
            var hrmData = hrmInfo.raw[hrmOffset];
            hrmOffset++;
            y = E.clip(170 - (hrmData*2),100,230);
            g.setColor(g.theme.fg).lineTo(hrmOffset, y);
            var print = ["HRM", hrmData ];
             Bluetooth.println(
               print.join(",")
               );
          }
        }
        Bangle.on('accel',function(a) {
          var d = [
            "ACC",
            Math.round(a.x*100),
            Math.round(a.y*100),
            Math.round(a.z*100)
            ];
          Bluetooth.println(d.join(","));
        })
        `,

connectWatch1(state) {
            let connection1;
            // disconnect if connected already
            if (connection1) {
                connection1.close();
                connection1 = undefined;
                state.watch1.connect = false
            }

            // Connect
            Puck.connect(function(c) {
                if (!c) {
                    // alert("Couldn't connect!");
                    // return;
                    state.watch1.connect = false
                    this.connectWatch1()
                }
                connection1 = c;
                state.watch1.connect = true
                    // console.log(connection)
                    // Handle the data we get back, and call 'onLine'
                    // whenever we get a line
                var buf = "";
                connection1.on("data", function(d) {
                    buf += d;
                    var l = buf.split("\n");
                    buf = l.pop();
                    l.forEach(
                        (line) => {
                            var d = line.split(',')
                            if (d[0] == 'ACC') {
                                // we have an accelerometer reading
                                state.watch1.accelX = parseInt(d[1]) / 100
                                state.watch1.accelY = parseInt(d[2]) / 100
                                state.watch1.accelZ = parseInt(d[3]) / 100
                            } else if (d[0] == 'HRM') {
                                // we have an accelerometer reading
                                state.watch1.hrm = parseInt(d[1])
                            }

                            // console.log("RECEIVED:" + state.watch1);
                        }
                        // console.log('RECEIVED:' + line)
                    );
                });
                // First, reset the Bangle
                connection1.write("reset();\n", function() {
                    // Wait for it to reset itself
                    setTimeout(function() {
                        // Now upload our code to it
                        connection1.write(
                            "\x03\x10if(1){" +
                            state.bangleCode +
                            "}\n",
                            function() {
                                console.log("Ready...");
                            }
                        );
                    }, 1500);
                });
            });
        },

thank you for your good source of reconnect!😀