update uuid

lib/util/index.js

@@ -37,3 +37,13 @@ export function getPointDistance (pointOne, pointTwo) {
 
   return Math.sqrt(minusX * minusX + minusY * minusY)
 }
+
+export function getUuid() {
+  let d = new Date().getTime();
+    const uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
+      var r = (d + Math.random()*16)%16 | 0;
+      d = Math.floor(d/16);
+      return (c=='x' ? r : (r&0x7|0x8)).toString(16);
+   });
+  return uuid;
+}