How can I pass variable in my fetch request

Question

I'm using react native and try to understand some examples.

I've got a problem

I'm trying to pass latitude in my fetch but I've got a problem who say me "latitude" don't exist

class App extends React.Component {
constructor() {
super();
this.state = {
  region: {
    latitude: LATITUDE,
      longitude: LONGITUDE,
      latitudeDelta: LATITUDE_DELTA,
      longitudeDelta: LONGITUDE_DELTA,
  },
  markers: [],
  loaded: false
}

}

componentDidMount() {
navigator.geolocation.getCurrentPosition(
  (position) => {
    console.log(position);
    this.setState({
      region: {
        latitude: position.coords.latitude,
        longitude: position.coords.longitude,
        latitudeDelta: LATITUDE_DELTA,
        longitudeDelta: LONGITUDE_DELTA,
      }
    });
  },
  (error) => this.setState({ error: error.message }),
  { enableHighAccuracy: false, timeout: 200000, maximumAge: 1000 },
  );
  this.getLocations()
}


getLocations(){
  return fetch('https://***&geofilter.distance='+latitude+'%2C2.3883402698750875%2C2000') //here
  .then(response => response.json())
  .then(responseData =>{
    var markers = [];

Can you help me, thanks:)

Answer 1

In getLocations , you're trying to use a latitude variable, but there is none in scope there. You may have wanted this.state.region.latitude .

If you're trying to use this.state.region.latitude , though, you need to move your call to getLocations in componentDidMount so that it's inside a state change completion handler:

componentDidMount() {
  navigator.geolocation.getCurrentPosition(
    (position) => {
      console.log(position);
      this.setState({
        region: {
          latitude: position.coords.latitude,
          longitude: position.coords.longitude,
          latitudeDelta: LATITUDE_DELTA,
          longitudeDelta: LONGITUDE_DELTA,
        }
      },
      () => {                   // ***
        this.getLocations();    // ***
      });                       // ***
    },
    (error) => this.setState({ error: error.message }),
    { enableHighAccuracy: false, timeout: 200000, maximumAge: 1000 },
  );
  // *** Not here
}

Answer 2

You are storing your latitude in state so you need to call it as this.state.region.latitude

return fetch('https://***&geofilter.distance='+this.state.region.latitude+'%2C2.3883402698750875%2C2000')

Answer 3

Try using your fetch like this:

return fetch('https://***&geofilter.distance='+this.state.region.latitude+'%2C2.3883402698750875%2C2000')