App.js

/* ... */
import YelpService from './app/services/yelp'

export default App extends Component {

  /* ... */

  getCoffeeShops = async () => {
    const { latitude, longitude } = this.state.region;
    const userLocation = { latitude, longitude };
    const coffeeShops = await YelpService.getCoffeeShops(userLocation);
    this.setState({ coffeeShops });
  };

  getLocationAsync = async () => {

    /* ... */

    // Add this line!
    await this.getCoffeeShops();
  }

  render() {
    const { region, coffeeShops } = this.state;
    return (
      <SafeAreaView style={styles.container}>
        <Map region={region} places={coffeeShops} />
      </SafeAreaView>
    );
  }
}