React function returns the last item in the JSON instead of mapping all of them

Question

const ZoomToLocation = ({latitude, longitude}) => {
  const map = useMapEvents({
    click() {
    map.setView([latitude, longitude], 15)
    }
  })
  return null
}

function MyMap() {
return(
  <MapContainer>
    {loc.map(loc => (
     <Marker 
     key={loc.properties.id} 
     position={[loc.properties.y, loc.properties.x]}>
       <ZoomToLocation latitude={loc.properties.y} longitude={loc.properties.x}/>
     </Marker>
          ))
     }
  </MapContainer>
)}

It maps everything in the <Marker> component as I would expect, but doesn't do it in <ZoomToLocation>. Instead, it just returns the last item in the JSON.

Any idea what I'm doing wrong?

what do you get if you `console.log(loc)` within the `loc.map(...)`? — Ross, Jun 18 '22 at 17:20
@Ross I get the correct JSON object. When the map renders all components and their props are rendered correctly. I expected that would behave in the same way as it is rendered within the map function. — Gatnik, Jun 18 '22 at 17:44

Ian A · Accepted Answer · 2022-06-23T06:51:42.577

Instead of using <ZoomToLocation>, you could use the click event handler of <Marker> like this:

{loc.map((l) => (
  <Marker
    key={l.properties.id}
    position={[l.properties.y, l.properties.x]}
    eventHandlers={{
      click: (e) => {
        map.flyTo(e.latlng, 15);
      },
    }}
  ></Marker>
))}

This will centre the map on the latlng property of a marker when you click on it.

You'll need to add the following so you can get a reference to map:

const [map, setMap] = useState(null);

and set the map using whenCreated:

<MapContainer
  ...
  whenCreated={setMap}
>

There's a full working demo here.

React function returns the last item in the JSON instead of mapping all of them

1 Answers1