Observable task queuing

Question

Observable task queuing

Here's the scenario: In my application, the user can tap a button to trigger a task that takes 2 seconds to complete. I want to set up a queue to run these tasks one after another, in sequence.

I am working with Ionic 3 and TypeScript.

What would be the most effective approach for accomplishing this?

javascript typescript ionic-framework ionic3 observable

Answer 1

Answer №1

To utilize the functionality of RxJS and ensure sequential execution, simply obtain a reference to the button, subscribe to the click event stream, and employ the flatMap method to delegate the click event to an asynchronous function. With RxJS, you can maintain order without worrying about managing state.

Here is an example:

ionViewDidLoad() {
  // Obtain a reference to the button (method of obtaining it doesn't matter)
  const button = document.getElementById('queueEventButton')

  // Create a stream of click events
  Observable.fromEvent(button, 'click')
    .flatMap(this.doTask) // Delegate each click event to the async process
    .scan( (count: number) => count + 1, 0) // Counts mouse clicks for demonstration purposes
    .subscribe(count => console.log(`Response received for click #${count}!`))
}

// Example async task simulating two seconds of processing
doTask(event: Event): Observable<Event> {
  return Observable.fromPromise(new Promise(resolve => {
    setTimeout(() => resolve(event), 2000)
  }))
}

Answer 2

To utilize the functionality of RxJS and ensure sequential execution, simply obtain a reference to the button, subscribe to the click event stream, and employ the flatMap method to delegate the click event to an asynchronous function. With RxJS, you can maintain order without worrying about managing state.

Here is an example:

ionViewDidLoad() {
  // Obtain a reference to the button (method of obtaining it doesn't matter)
  const button = document.getElementById('queueEventButton')

  // Create a stream of click events
  Observable.fromEvent(button, 'click')
    .flatMap(this.doTask) // Delegate each click event to the async process
    .scan( (count: number) => count + 1, 0) // Counts mouse clicks for demonstration purposes
    .subscribe(count => console.log(`Response received for click #${count}!`))
}

// Example async task simulating two seconds of processing
doTask(event: Event): Observable<Event> {
  return Observable.fromPromise(new Promise(resolve => {
    setTimeout(() => resolve(event), 2000)
  }))
}

Observable task queuing

Answer №1

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