Angular: Knowing the right time to use the subscribe method for data submission

Question

Angular: Knowing the right time to use the subscribe method for data submission

I'm feeling a bit lost and hoping someone could assist me in comprehending the use of .subscribe in Angular 2 RxJS.

If I have a webpage with a button to submit form data, do I need to subscribe to post information or should I opt for using a promise?

As far as I understand it, when you subscribe and then click the button again, you'll end up with multiple subscriptions. I know one solution is to kill the subscription during destruction, but that's not what I'm asking about.

My question is, if the form persists until hitting the home button and clearing upon submission to enter more data, should I go for Promise instead of Subscribe? Subscribe seems to act like a newsletter - the more you subscribe, the more newsletters you receive.

So, what is the better approach for repeatedly submitting data without creating multiple subscriptions?

myObsFunc(dataToSend).subscribe(err => console.log(err), () => console.log(success));

or

myObsFunc(dataToSend).toPromise().then().catch(e => console.log(e));

angular typescript angular2-forms rxjs5 angular2-observables

Answer 1

Answer №1

Imagine observables like personalized newsletters. Each subscriber receives their own unique newsletter, tailored just for them. These newsletters are not sent to just anyone, but only to those who have subscribed.

Unlike promises, observables can provide multiple values over time. By keeping your subscription open, you will continue to receive new newsletters on a regular basis. You simply sit back and wait for them to arrive in your inbox whenever the sender decides to send them out.

One notable difference between observables and promises is that observables are cancelable. If you no longer wish to receive the newsletter, you can easily unsubscribe. In contrast, promises cannot be canceled once they have been handed to you. Once a promise is made, the process leading to its fulfillment is already in motion, and there is no way to stop it from completing.

Answer 2

Imagine observables like personalized newsletters. Each subscriber receives their own unique newsletter, tailored just for them. These newsletters are not sent to just anyone, but only to those who have subscribed.

Unlike promises, observables can provide multiple values over time. By keeping your subscription open, you will continue to receive new newsletters on a regular basis. You simply sit back and wait for them to arrive in your inbox whenever the sender decides to send them out.

One notable difference between observables and promises is that observables are cancelable. If you no longer wish to receive the newsletter, you can easily unsubscribe. In contrast, promises cannot be canceled once they have been handed to you. Once a promise is made, the process leading to its fulfillment is already in motion, and there is no way to stop it from completing.

Answer 3

Answer №2

Observable is like a flowing river of data. This snippet of code can be your guide to understanding it better.

import {interval} from "rxjs/observable/interval";

let observable = interval(1000); //emits an event every second

let subscription = observable.subscribe((data) => {
  //perform actions for each data emission
  console.log(data);
}, (error) => {
  //handle errors during observation
}, () => {
  //actions on stream completion
});

//unsubscribe to stop observing
subscription.unsubscribe();

Answer 4

Observable is like a flowing river of data. This snippet of code can be your guide to understanding it better.

import {interval} from "rxjs/observable/interval";

let observable = interval(1000); //emits an event every second

let subscription = observable.subscribe((data) => {
  //perform actions for each data emission
  console.log(data);
}, (error) => {
  //handle errors during observation
}, () => {
  //actions on stream completion
});

//unsubscribe to stop observing
subscription.unsubscribe();

Angular: Knowing the right time to use the subscribe method for data submission

Answer №1

Answer №2

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