How to make a flag counter with react-native-beacons-manager - react-native

Question

Scenario
Our app aims to detect beacons placed inside the restaurants our app
uses react-native-beacons-manager
When our app detects a beacon, I have developed a cloud function that accepts the beacon's major key and use it to query data of that restaurant from my database
The Cloud function then sends a push notification on the user about the restaurant details.
The Problem
The way I detect the beacons is not stable. this is my flow. I created a function located at
this.beaconsDidRangeEvent = Beacons.BeaconsEventEmitter.addListener(
//function-here
);
I can receive the beacons information like uuid, major and minor key and proximity (immediate, near, far, unknown) . Now inside that function I use the major key to determine the individuality of each beacons. Now, I've made a condition like this:
let beaconArr = data.beacons;
console.log(beaconArr);
console.log(count);
if (beaconArr.length > 0) {
console.log("beacons detected!");
let major = data.beacons[0].major;
let prox = data.beacons[0].proximity;
if ((prox === "near" || prox === "far") && beaconFlag === false && count === 0) {
console.log("beacon Action");
this.props.beaconAction(major);
this.props.createCheckInHistory(user.uid);
beaconFlag = true;
count++;
} else {
console.log("counter turned to 1!");
console.log(data);
beaconFlag = true;
}
} else {
console.log("no beacons detected!");
count = 0;
beaconFlag = false;
}
Expected Result
I expect that the functions inside the condition is true will only fire once.
Actual Result
Sometimes, its ok sometimes its not. even if im still at the range of the beacon, suddenly the beacon's array got 0. Then suddenly i'll receive a push notification again and again.
componentDidMount() Code
componentDidMount() {
this.props.selectedIcon('map');
firebase
.messaging()
.getInitialNotification()
.then(notification => {
console.log("Notification which opened the app: ", notification);
});
const user = firebase.auth().currentUser;
let count = 0;
let beaconFlag = false;
// will be set as a reference to "regionDidEnter" event:
this.beaconsDidRangeEvent = Beacons.BeaconsEventEmitter.addListener(
"beaconsDidRange",
_.throttle(data => {
let beaconArr = data.beacons;
console.log(beaconArr);
console.log(count);
if (beaconArr.length > 0) {
console.log("beacons detected!");
let major = data.beacons[0].major;
let prox = data.beacons[0].proximity;
if ((prox === "near" || prox === "far") && beaconFlag === false && count === 0) {
console.log("beacon Action");
this.props.beaconAction(major);
this.props.createCheckInHistory(user.uid);
beaconFlag = true;
count++;
} else {
console.log("counter turned to 1!");
console.log(data);
beaconFlag = true;
}
} else {
console.log("no beacons detected!");
count = 0;
beaconFlag = false;
}
}, 3000)
);
// monitoring events
this.regionDidEnterEvent = Beacons.BeaconsEventEmitter.addListener(
"regionDidEnter",
data => {
console.log("monitoring - regionDidEnter data: ", data);
}
);
// Monitoring: Listen for device leaving the defined region
this.regionDidExitEvent = Beacons.BeaconsEventEmitter.addListener(
"regionDidExit",
data => {
console.log("monitoring - regionDidExit data: ", data);
}
);
}

Answer 1

This is a common problem when ranging in beacon apps. Sometimes the detected beacons will briefly drop out then come back again. This can be solved by a software filter where you keep track of all beacons you have recently seen, and only perform an operation of it has not happened recently. In your case, you may use the major as the key to the index into the filter object.
// scope this globally
var minimumRetriggerMillis = 3600 * 1000; // 1hr
var recentTriggers = {};
// Before executing your trigger action:
var now = new Date().getTime();
if (recentTriggers[minor] == null || now-recentTriggers[minor] > minimumRetriggerMillis) {
recentTriggers[minor] = now;
// TODO: execute trigger logic here
}