test.js

getCurrentLocation = async () => {
    return new Promise((resolve, reject) => {
        navigator.geolocation.getCurrentPosition(
            (position) => {
              resolve({
                latitude: parseFloat(position.coords.latitude),
                longitude: parseFloat(position.coords.longitude),
                latitudeDelta: 5,
                longitudeDelta: 5,
              })
            },
            reject,
            {
              enableHighAccuracy: true,
              timeout: 10000,
            }
          );
    })
  };
  

  getTrailData = async ({ latitude: lat, longitude: lon }) => {
    //GET request
    var url = new URL("https://www.hikingproject.com/data/get-trails?");
    var params = {
      lat,
      lon,
      maxDistance: "10",
      maxResults: "5",
      key: "200910989-d4cede628914dc93c09781fa51730b39",
    };
    Object.keys(params).forEach((key) =>
      url.searchParams.append(key, params[key])
    );
    alert(url);
    return fetch(url)
      .then((response) => response.json())
      //If response is in json then in success
      .then((responseJson) => {
        // alert(responseJson.trails.length);
        this.setState({
          dataSource: responseJson.trails,
          loaded: true,
        });
        // alert(this.state.dataSource.length);
      })
      //   trails(responseJson.trails);
      //If response is not in json then in error
      .catch((error) => {
        //Error
        this.setState({
          loaded: true,
          error: true,
        });
        console.error(error);
      });
  };

  try {
    const region = await getCurrentLocation()
    this.mapView.animateToRegion(region, 1000)
    await getTrailData()
  } catch (error) {
      console.error(error)
  }