fix scroll jank

static/map.js

@@ -21,6 +21,7 @@ let center = [0, 0];
 let lastPos = [0, 0];
 let isMouse = false;
 let zoom = 1;
+let timer = 0;
 
 let id = '';
 
@@ -69,16 +70,26 @@ function mouseDown(e) {
 }
 
 function wheel(e) {
+    document.body.style.overflow = 'hidden';
+
+    if (timer != 0) clearTimeout(timer);
+
+    timer = setTimeout(function() {
+        document.body.style.overflow = '';
+    },400)
+
     mpos[0] -= lastPos[0];
     mpos[1] -= lastPos[1];
 
-    mpos[0] *= (1.005 ** -e.deltaY)
+    let f = (2 ** -(e.deltaY/256));
-    mpos[1] *= (1.005 ** -e.deltaY)
+
+    mpos[0] *= f;
+    mpos[1] *= f;
 
     mpos[0] += lastPos[0];
     mpos[1] += lastPos[1];
 
-    zoom *= (1.005 ** -e.deltaY)
+    zoom *= f;
 }
 
 function move() {