RxJS - MacKittipat/note-developer GitHub Wiki

It is a library for reactive programming.
Library for handling asynchronous data stream.
Promise vs RxJS
- Promise work with single value such as single API call.
- RxJS work with stream of data such as mouse click event.
Observable is similar to wrapper of stream of data
- https://rxjs.dev/api/index/class/Observable
- It's a collection of item over time.
Observer :
- https://rxjs.dev/api/index/interface/Observer
Subscriber :
- https://rxjs-dev.firebaseapp.com/api/index/class/Subscriber
Subscription :
- https://rxjs-dev.firebaseapp.com/api/index/class/Subscription
Subject :
- https://rxjs-dev.firebaseapp.com/api/index/class/Subject
- Similar to Hot observable
Hot :
- Multicast
- Allow broadcast same value to multiple subscriber.
- Data is produced outside the Observable
Cold :
- Unicast. Subscriber receive the same value.
- Don't emit value until it is subscribed.
- Data is produced inside the Observable

const { Observable } = require("rxjs");

let observable = new Observable((subscriber) => {
  subscriber.next(1);
  subscriber.next(2);
  subscriber.complete();
});

let observer = {
  next: (item) => {
    console.log(item);
  },
  error: (error) => {
    console.log(error);
  },
  complete: () => {
    console.log("Completed.");
  },
};

let subscription = observable.subscribe(observer);
subscription.unsubscribe();

Sample :

const { of, from, Observable } = require('rxjs');
const { map, filter } = require('rxjs/operators');

of('hello').subscribe(i => console.log(i));
from('hello').subscribe(i => console.log(i));
let observable = new Observable(subscriber => {
    subscriber .next(1);
    subscriber .next(2);
    subscriber .next(3);
    subscriber .complete();
})
let subscription = observable.subscribe(i => {
    console.log(i);
})

Reference :