angular-docs-cn/aio/content/examples/observables/src/geolocation.ts

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1.1 KiB
TypeScript

import { Observable } from 'rxjs';
// #docregion
// Create an Observable that will start listening to geolocation updates
// when a consumer subscribes.
const locations = new Observable((observer) => {
// Get the next and error callbacks. These will be passed in when
// the consumer subscribes.
const {next, error} = observer;
let watchId;
// Simple geolocation API check provides values to publish
if ('geolocation' in navigator) {
watchId = navigator.geolocation.watchPosition(next, error);
} else {
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);
// #enddocregion