React-native doesn't have Nearby API in its core, but you could wrap native code in a manager or take a look at react-native-invoke, you can:

Invoke any native code directly from Javascript in React Native (without wrapping it first with a native manager)

Alternatively, you can use this approach if you have the coordinates of the other users and you want to check if they are nearby:

You can get the user location with Geolocation API

navigator.geolocation.getCurrentPosition( (position) => { myLocation = position.coords }, error => alert(error), { enableHighAccuracy: false, timeout: 20000, maximumAge: 1000*60*5 })

Then you could calculate the distance between the user and places (if you have their coordinates) using this function:

export const calculateDistance = (place, me)=>{ const toRadians = (angle)=>{ return angle * Math.PI / 180 } let lat1 = place.latitude let lon1 = place.longitude let lat2 = me.latitude let lon2 = me.longitude var R = 6371e3; // metres var phi1 = toRadians(lat1) var phi2 = toRadians(lat2) var deltaPhi = toRadians((lat2-lat1)) var deltaLambda = toRadians((lon2-lon1)) var a = Math.sin(deltaPhi/2) * Math.sin(deltaPhi/2) + Math.cos(phi1) * Math.cos(phi2) * Math.sin(deltaLambda/2) * Math.sin(deltaLambda/2); var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); var d = R * c; return d}

Credits: Movable Type Scripts