Tips for handling numerous observables in Angular 7

Question

Tips for handling numerous observables in Angular 7

I am working on an Angular 7 application that deals with a total of 20 sensor data. My goal is to receive data from a selected sensor every 5 seconds using observables. For example:

var sensorId = ""; // dynamically chosen from the web interface
var sensorData$ = interval(5000).pipe()
sensorData$.subscribe() // etc..

I will be selecting multiple sensors and initiating data retrieval via subscription using intervals. How can I manage these observables effectively? What's the best approach to handle them?

In addition, I have the capability to add any new sensor at any given time.

javascript angular typescript rxjs angular7

Answer 1

Answer №1

If you're looking for a solution, I recommend utilizing Subject and mergeMap.

To elaborate, create a single Subject to emit new sensorIds when chosen by the user in the UI. Subsequently, subscribe to this Subject and utilize mergeMap within your subscription method to handle all sensor values effectively.

Let's examine a sample code snippet below:

private sensorIdSubject = new Subject();

ngOnInit() {
  this.sensorIdSubject.pipe(
    mergeMap(sensorId => 
      interval(5000).pipe(switchMap(() => this.getSensorData(sensorId)))
  ).subscribe(sensorData => {
    // At intervals of 5 seconds, retrieve data for selected sensorIds from the UI
    // and emit new values in the subscribe function as they are consolidated.
  })
}

public chooseSensor(sensorId) {
  this.sensorIdSubject.next(sensorId);
}

Does this approach align with your requirements? If modifications are necessary, feel free to provide feedback in the comments section for further adjustments.

Answer 2

If you're looking for a solution, I recommend utilizing Subject and mergeMap.

To elaborate, create a single Subject to emit new sensorIds when chosen by the user in the UI. Subsequently, subscribe to this Subject and utilize mergeMap within your subscription method to handle all sensor values effectively.

Let's examine a sample code snippet below:

private sensorIdSubject = new Subject();

ngOnInit() {
  this.sensorIdSubject.pipe(
    mergeMap(sensorId => 
      interval(5000).pipe(switchMap(() => this.getSensorData(sensorId)))
  ).subscribe(sensorData => {
    // At intervals of 5 seconds, retrieve data for selected sensorIds from the UI
    // and emit new values in the subscribe function as they are consolidated.
  })
}

public chooseSensor(sensorId) {
  this.sensorIdSubject.next(sensorId);
}

Does this approach align with your requirements? If modifications are necessary, feel free to provide feedback in the comments section for further adjustments.

Answer 3

Answer №2

To consolidate multiple observables into one and receive all the emitted values, you can utilize rxjs' forkJoin method.

This allows you to handle a group of observables collectively, enabling you to apply pipe operators and perform various operations on the combined data.

For example:

let sensors = forkJoin(observable1, observable2)

sensors.subscribe(
   sensorData => {
      // Handle the object containing data from your observables
   }
)

If you have varying numbers of observables emitting different values, consider using BehaviorSubject in the following manner:

let sensors = new BehaviorSubject<Array<Observables<yourType>>([])

sensors.next([newArrayOfObservables])

sensors.subscribe(
    sensors$ => {
      sensor$.forEach(sensor => {
        sensor.subscribe( // Perform your logic)
      }
    }
)

This approach allows for adding or removing observables dynamically. Keep in mind that ForkJoin only emits values when all observables complete, triggering only one emission event.

Lastly, remember to properly manage your unsubscriptions to avoid memory leaks.

Answer 4

To consolidate multiple observables into one and receive all the emitted values, you can utilize rxjs' forkJoin method.

This allows you to handle a group of observables collectively, enabling you to apply pipe operators and perform various operations on the combined data.

For example:

let sensors = forkJoin(observable1, observable2)

sensors.subscribe(
   sensorData => {
      // Handle the object containing data from your observables
   }
)

If you have varying numbers of observables emitting different values, consider using BehaviorSubject in the following manner:

let sensors = new BehaviorSubject<Array<Observables<yourType>>([])

sensors.next([newArrayOfObservables])

sensors.subscribe(
    sensors$ => {
      sensor$.forEach(sensor => {
        sensor.subscribe( // Perform your logic)
      }
    }
)

This approach allows for adding or removing observables dynamically. Keep in mind that ForkJoin only emits values when all observables complete, triggering only one emission event.

Lastly, remember to properly manage your unsubscriptions to avoid memory leaks.

Tips for handling numerous observables in Angular 7

Answer №1

Answer №2

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