Location

Install

npx expo install expo-location

import { Location } from '@ng-native/expo/location';

The smallest thing that works

import { Component, inject, type OnDestroy } from '@angular/core';
import { Text } from '@ng-native/components';
import { Location } from '@ng-native/expo/location';

@Component({
  selector: 'app-run',
  imports: [Text],
  template: `
    @if (location.position(); as here) {
      <text>{{ here.latitude }}, {{ here.longitude }}</text>
    }
  `,
})
export class Run implements OnDestroy {
  protected readonly location = inject(Location);
  private stop = () => {};

  async start(): Promise<void> {
    this.stop = await this.location.start({ accuracy: 'high', distance: 10 });
  }

  ngOnDestroy(): void {
    this.stop();
  }
}

Reading a position

• position is a signal: null until something has been read, then the latest fix - latitude, longitude, altitude, accuracy, heading, speed and timestamp. altitude, accuracy, heading and speed are null where the platform does not know them.
• current(accuracy) reads the position once and returns it (or null, without the permission or the module).
• start({ accuracy, distance, interval }) follows the position into the signal, resolving to the function that stops watching. distance is meters moved before the next update; interval is milliseconds between updates, Android only - iOS updates on distance moved, not on a timer.
• The accuracy is a name, not Expo's numeric enum: lowest, low, balanced (the default), high, highest or navigation. Worth choosing deliberately: navigation keeps the GPS hot.

Both current() and start() ask for the foreground permission themselves, via location.permission (see Permissions), and do nothing without it - current() resolves to null, start() to a stop function that does nothing. Location in the background is not wrapped by this service; use expo-location's own background API directly if you need it.

Add to Info.plist:

<key>NSLocationWhenInUseUsageDescription</key>
<string>Allow this app to use your location</string>

Android's ACCESS_COARSE_LOCATION and ACCESS_FINE_LOCATION permissions are added automatically by the module's config plugin.

An address and a point

geocode(address) answers the places an address could be, best match first, from the platform's own geocoder, and reverseGeocode(coordinates) the addresses at a point. On iOS they ask for no permission, since Apple's geocoder does not need one. On Android they ask for the foreground permission as current() does, and answer an empty list without it, because expo-location refuses to geocode there without it. Both answer an empty list for an address the geocoder does not know, and off a device. In an app built without expo-location they throw MissingModuleError, as the rest of the service does.

const [place] = await this.location.geocode('10 Downing Street, London');
if (place) this.marker.set(place); // { latitude, longitude }

Without the module

On iOS and Android, a missing expo-location - never installed, or installed without the app being rebuilt since - leaves the service made, so injecting it does not throw. A call, or a read of a value only the module knows, throws a MissingModuleError. Its message names the module and the commands that fix it; see Using a module.

On the web, and in a test that provides no fake, permission reports denied with canAskAgain: false. current() resolves to null and start() to a stop function that does nothing, exactly as though the permission had been refused.

Reference