feat(utils): add findNearest function to calculate closest point

EnvelopeGenerator.Web/wwwroot/js/util.js

@@ -12,4 +12,15 @@ function detailedCurrentDate() {
         second: '2-digit',
         timeZoneName: 'shortOffset'
     }).format();
+}
+
+function findNearest(origin, getX, getY, ...dests) { 
+    const distanceToOrigin = (point) => Math.sqrt((getX(origin) - getX(point))**2 + (getY(origin) - getY(point))**2);
+    return dests.reduce(
+        (nearest, dest) => {
+            const dist = distanceToOrigin(dest);
+            return dist < nearest.dist ? {dist, dest} : nearest;
+        },
+        {dist: Infinity, dest: null}
+    ).dest;
 }