HR crashing my app

[ac_devel]

I have an app and it basically runs through the night. 
Before, I would only access the the accelerometer data but I added a feature so that I can have a continuous reading of the HR. 

Here is the main piece of code. I am hoping that maybe a pair of eyes more can help me figure why my app crashes after adding the HR reader (it gets the HR values every 30 seconds). 

import { Accelerometer } from "accelerometer";
import { HeartRateSensor } from "heart-rate";
import { vibration } from "haptics";
import sleep from "sleep";
import * as scientific from "scientific";
import { today } from "user-activity";
import { me as appbit } from "appbit";
import * as document from "document";
import * as fs from "fs";

appbit.appTimeoutEnabled = false;
const bEndSession = document.getElementById("bEndSession");
const bAActive = document.getElementById("bAActive");
const bASleepy = document.getElementById("bASleepy");
const displayText = document.getElementById("textBox");
const timeBox = document.getElementById("timeBox");
var _today = new Date();
var _time = _today.getHours() + ":" + _today.getMinutes() + ":" + _today.getSeconds();

export class Kobe {
    constructor(kobeId) {
        console.log("Constructor");
        this.accelerometer = new Accelerometer({ frequency: 10, batch: 10 });
        this.hrm = new HeartRateSensor();
        this.ss = 0;
        this.kk = 0;
        this.tid = 0;
        this.noResCount = 0;
        this.maxNoResponse = 9;
        this.movementFound = false;
        this.noMovementStDev = 0;
        this.movementStDev = 0
        this.startTime = new Date().getTime();
        this.maxTime = 30; //30minutes
        this.fallingAsleep = 0;
        this.fitbitData = {};
        this.userInfo = {};
        // 
        this.currentSteps = today.adjusted.steps;
        this.bedActive = true;
        this.probeOn = true;
        this.awake = false;
        this.exiting = false;
        this.stepsArr = []
        //bedSleepy = false;

        this.startAccel();
        displayText.text = `Probe ON: ${this.maxTime} mins.`
        _today = new Date();
        _time = _today.getHours() + ":" + _today.getMinutes();
        timeBox.text = _time;
    }

    //data
    setFitbitData = (kobeId) => {
        //console.log("I am setFitbitData")
        var _date = new Date();
        this.fitbitData = {
            uid: `${kobeId.deviceId}_${kobeId.userType}${kobeId.userId}`,
            sessionDate: Date.now(), //ts in UTC
            awakeTime: 0,
            sleepData: [],
            hrData: [],
            userMeta: {
                withPpets: false,
                withPartner: false,
                withFans: false,
                tzOffset: _date.getTimezoneOffset(),
                deviceId: kobeId.deviceId,
                esId: `${kobeId.userType}${kobeId.userId}`
            },
            userSteps: [],
            sleepStarts: [],
            kobeRecall: [],
            badSession: false
        }
    }
    //startAccel();
    //}

    startAccel() {
        //console.log("I am startAccel")
        this.accelerometer.addEventListener("reading", () => {
            this.ss = scientific.std(this.accelerometer.readings.x) + scientific.std(this.accelerometer.readings.y) + scientific.std(this.accelerometer.readings.z);
            console.log(`ss: ${this.ss}`);
        });
        this.accelerometer.start();


        if (HeartRateSensor) {
            console.log("This device has a HeartRateSensor!");
            //const hrm = new HeartRateSensor();
            this.hrm.addEventListener("reading", () => {
                console.log(`Current heart rate: ${this.hrm.heartRate}`);
            });
            this.hrm.start();
        } else {
            console.log("This device does NOT have a HeartRateSensor!");
        }
    }

    checkForMovement = () => {
        var ss1 = scientific.std(this.accelerometer.readings.x) + scientific.std(this.accelerometer.readings.y) + scientific.std(this.accelerometer.readings.z);
        console.log(`checkForMovement ${this.kk} ${this.ss} ${this.ss1}`);
        // disc1.crossCountT();
        if (this.ss > 5.0) {
            this.noResCount = 0;
            this.fallingAsleep = 0;
            this.movementStDev = ss;
            console.log(`movement detected ${kk} ${ss}`);
        } else {
            this.noResCount++;
            if (this.noResCount > 0 && this.noResCount <= 3) {
                this.fallingAsleep = Date.now();
            }
            console.log(`movement nope ${this.kk} ${this.ss}`);
            this.noMovementStDev = this.ss;
        }
        console.log(`noResCount: ${this.noResCount}`);
        //console.log(inWakeWindow);
        this.movementFound = (this.noResCount < 3) ? true : false;

        this.userInfo = {
            //action: inWakeWindow ? 'Awake Nudge' : 'Buzzed',
            action: 'Buzzed',
            timeStamp: Date.now(),
            movement: this.movementFound,
            stDev: this.movementFound ? this.movementStDev : this.noMovementStDev,
            userState: sleep.state,
            awakeActive: this.bedActive,
            awakeSleepy: !this.bedActive
        }

    }

    sendUserInfo = () => {
        // userData.push(userInfo)
        this.fitbitData.sleepData.push(this.userInfo);
        console.log(`User info: ${JSON.stringify(this.fitbitData, null, 4)}`);
        //console.log(util.inspect(myObject, false, null, true /* enable colors */))
        var fileName = `${this.fitbitData.sessionDate}`;
        fs.writeFileSync(`${fileName}.json`, this.fitBitData, "json");
        //transferFile(fileName);
    }

    pingUser = () => {
        console.log('Vibrating');
        vibration.start("nudge");
        //vibration.start("nudge-max");
        this.kk++;
        setTimeout(this.checkForMovement, 2 * 1000);
        setTimeout(this.checkForMovement, 3 * 1000);
        setTimeout(this.checkForMovement, 4 * 1000);
        setTimeout(this.sendUserInfo, 4 * 1000)
        // console.log("hi! im here dear!");
    }

    clear = () => {
        if (this.noResCount >= this.maxNoResponse) {
            clearInterval(this.tid);
            console.log("Probe should be off!!")
            //accel.stop();
            // exit from
            this.probeOn = false;
            //bEndSession.text = `End Session`
            displayText.text = 'Probe OFF'
            displayText.style.fill = "fb-red"
            bAActive.text = 'Awake in bed';
            bAActive.style.fill = "#FFA07A";
            bASleepy.text = 'Going to sleep'
            bASleepy.style.fill = "#FFA07A";
            const exitMessage = {
                action: 'Normal Exit',
                timeStamp: Date.now(),
                movement: this.movementFound,
                stDev: this.movementFound ? this.movementStDev : this.noMovementStDev,
                userState: sleep.state,
                awakeActive: this.bedActive,
                awakeSleepy: !this.bedActive
            }
            this.fitbitData.sleepStarts.push(this.fallingAsleep);
            this.fitbitData.sleepData.push(exitMessage);
            this.noResCount = 0;

        }

        if (this.awake) {
            //accel.start();
            this.awake = false;
            this.fitbitData.kobeRecall.push(Date.now());
            clearInterval(this.tid);
            this.tid = setInterval(this.pingUser, 5 * 60 * 1000);
            //bEndSession.text = `End Session`
            displayText.text = 'Probe ON'
        }

        if (this.exiting) {
            //console.log('Clear -  exiting');
            clearInterval(this.tid);
            this.fitbitData.awakeTime = Date.now();
            // var _date = new Date();
            this.fitbitData.userSteps.push(this.stepsArr);
        }
        //console.log(`kk ${this.kk} ${this.tid}`);
    }

    stepCounter = () => {
        var prevSteps = this.currentSteps;
        var stepsTs = Date.now();
        this.currentSteps = today.adjusted.steps;
        var stepsDiff = this.currentSteps - prevSteps;
        if (stepsDiff > 0 && stepsDiff != null) {
            console.log(stepsDiff);
            // this.stepsArr.push({
            //     time: stepsTs,
            //     values: stepsDiff,
            // });
            this.fitbitData.userSteps.push({
                time: stepsTs,
                values: stepsDiff,
            })
        } else if (stepsDiff < 0 && stepsDiff != null) {
            // this.stepsArr.push({
            //     time: stepsTs,
            //     values: this.currentSteps,
            // })
            this.fitbitData.userSteps.push({
                time: stepsTs,
                values: this.currentSteps
            })
            prevSteps = this.currentSteps;
        } else {
            console.log("No movement");
        }
        

        // TIMER
        if (this.maxTime <= 0 && this.probeOn) {
            displayText.text = `Probe ON: Ok to sleep`;
        }
        else if (this.maxTime <= 0 && !this.probeOn) {
            displayText.text = `Probe OFF`;
        } else if (this.maxTime > 0 && !this.probeOn) { 
            displayText.text = `Probe OFF`;
        }else {
            this.maxTime--;
            displayText.text = `Probe ON: ${this.maxTime} mins.`
        }
        // if (new Date().getTime() - this.startTime >= 30 * 60 * 1000) {
        //     displayText.text = `Probe ON: Go sleep`;
        // } else { 
            
        //     displayText.text = `Probe ON: ${this.maxTime} mins.`
        // }
        // this.maxTime--;
    
        
        _today = new Date();
        _time = _today.getHours() + ":" + _today.getMinutes();
        timeBox.text = _time;

    }

    writeHr = () => {
        console.log(`HR iss ${this.hrm.heartRate}`);
        this.fitbitData.hrData.push({
            value: this.hrm.heartRate,
            timeStamp: Date.now()
        })
    }

    firstPing = () => {
        console.log('Vibrating');
        vibration.start("ping");

        const mex = {
            action: 'First push',
            timeStamp: Date.now(),
            movement: true,
            stDev: this.movementFound ? this.movementStDev : this.noMovementStDev,
            userState: sleep.state,
            awakeActive: this.bedActive,
            awakeSleepy: !this.bedActive
        }
        // userData.push(mex)
        this.fitbitData.sleepData.push(mex)
        // console.log(`User info: ${JSON.stringify(fitBitData)}`)
    }

    activeProbe = () => {
        console.log("This is active Probe");
        this.probeOn = true;
        bEndSession.text = `End Session`
        this.firstPing()
        this.tid = setInterval(this.pingUser, 5 * 60 * 1000)
        setInterval(this.clear, 2 * 1000)
        setInterval(this.writeHr, 30 * 1000);
        setInterval(this.stepCounter, 1 * 60 * 1000);
    }
}