CODEWITHSUNDEEP
javascriptreact-native
Ezequiel Perez
Ezequiel Perez

Reputation: 39

How can I assign an object to the correct object in array? React Native

I fetch this array from server :

[{
  "res_id": 0,
  "res_name": "string",
  "res_desc": "string",
  "res_address": "string"
},
etc
]

I have to display a list of markers on map, so I map my restos into marker to populate the coords, the first problem is with the data i get from server, its an adress, so then I call:

restos.forEach(x => FetchGeocoder(x.res_address));

To then fetch with geocoder:

const FetchGeocoder = async (address) => {
        const response = await fetch('https://maps.googleapis.com/maps/api/geocode/json?address=' +
            address + ',' +
            'CABA&key=' + "KEY")
        const responseData = await response.json();
        const markers = responseData.results[0].geometry.location;
        restos.forEach(x => {
            x.res_coords = {
                latitude: markers.lat,
                longitude: markers.lng
            }
        });
    };

The problem I cant resolve is that I get 3 coords objects, because I have 3 restos in my array, but only 1 coords object is assigned to all of my restos, instead of each coords beeing asigned to the correct resto.

Thanks in advance for any help or assistance!

Upvotes: 1

Views: 48

Answers (1)

Dacre Denny
Dacre Denny

Reputation: 30360

One option would be to make use of async/await to perform asynchronous function calls (ie to fetchGeocode()) during each iteration of the restos array.

For example, you could adapt your code to use the following (or similar) pattern:

/* Define async fetchGeocode() function that returns lat/lng data */
const fetchGeocode = async (address) => {
  const res = await fetch('https://maps.googleapis.com/maps/api/geocode/json' + 
                          '?address=' + address + ',CABA&key=' + API_KEY);

  const json = await res.json();
  const { lat, lng } = json.results[0].geometry.location;

  return {
    latitude: lat,
    longitude: lng
  };
};

// Async function adds coords to each resto
async function addCoordsToRestos(restos) => {

  // If restos undefined, or not an iterable array type then return
  // an empty array as a default response
  if(!Array.isArray(restos)) {
      return [];
  }

  // Iterate each resto
  for (const resto of restos) {

    // Mutate current resto by adding res_coords. Call fetchGeocode() 
    // with await to wait for async function to complete before next
    // iteration
    resto.res_coords = await fetchGeocode(resto.res_address);
  }

  // Return mutated restos array to next handler
  return restos
}

Usage would then look like this:

// If called inside an async function
await addCoordsToRestos( restos );

Or:

// If called as a promise
addCoordsToRestos( restos ).then(() => { console.log('done') });

Upvotes: 1

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