separate variable constants

packages/artplayer/src/events/viewInit.js

@@ -3,12 +3,13 @@ import { throttle, isInViewport } from '../utils';
 export default function viewInit(art, events) {
     const {
         option,
+        constructor,
         template: { $container },
     } = art;
 
     const scrollFn = throttle(() => {
-        art.emit('view', isInViewport($container, 50));
-    }, 200);
+        art.emit('view', isInViewport($container, constructor.SCROLL_GAP));
+    }, constructor.SCROLL_TIME);
 
     events.proxy(window, 'scroll', () => {
         scrollFn();