JSFiddle - React, Tailwind, and code Playground

JavaScript

/** Converts numeric degrees to radians */
if (typeof(Number.prototype.toRad) === "undefined") {
  Number.prototype.toRad = function() {
    return this * Math.PI / 180;
  }
}

navigator.geolocation.getCurrentPosition(function(position){
    calcPosition(position.coords.latitude,position.coords.longitude)
});
function calcPosition(lat1, lon1){
    var lat2 = 45.843295; 
    var lon2 = -87.020821; // 2 is location
    var R = 3963.1676; // radius in mi
    var x1 = lat2-lat1;
    var dLat = x1.toRad();  
    var x2 = lon2-lon1;
    var dLon = x2.toRad();  
    var a = Math.sin(dLat/2) * Math.sin(dLat/2) + 
    Math.cos(lat1.toRad()) * Math.cos(lat2.toRad()) * 
    Math.sin(dLon/2) * Math.sin(dLon/2);  
    var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
    var d = R * c; 
    alert("You are"+" "+d+" "+"miles away from our school")
}