subscribe to observable code example
Example 1: emit new value observable
const observable = new BehaviorSubject("initial value");
observable.subscribe({
next: (value) => console.log("The value is: ", value)
});
observable.next("a new value");
Example 2: rxjs .subscribe
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import { interval } from 'rxjs';
const observable = interval(1000);
const subscription = observable.subscribe(x => console.log(x));
// Later:
// This cancels the ongoing Observable execution which
// was started by calling subscribe with an Observer.
subscription.unsubscribe();
Example 3: observable tutorial angular
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// Create an Observable that will start listening to geolocation updates
// when a consumer subscribes.
const locations = new Observable((observer) => {
let watchId: number;
// Simple geolocation API check provides values to publish
if ('geolocation' in navigator) {
watchId = navigator.geolocation.watchPosition((position: Position) => {
observer.next(position);
}, (error: PositionError) => {
observer.error(error);
});
} else {
observer.error('Geolocation not available');
}
// When the consumer unsubscribes, clean up data ready for next subscription.
return {
unsubscribe() {
navigator.geolocation.clearWatch(watchId);
}
};
});
// Call subscribe() to start listening for updates.
const locationsSubscription = locations.subscribe({
next(position) {
console.log('Current Position: ', position);
},
error(msg) {
console.log('Error Getting Location: ', msg);
}
});
// Stop listening for location after 10 seconds
setTimeout(() => {
locationsSubscription.unsubscribe();
}, 10000);