thumbnail tool init

packages/artplayer-tool-thumbnail/src/index.js

@@ -1 +1,8 @@
 import './index.scss';
+
+export default class ArtplayerToolThumbnail {
+    constructor(el) {
+        this.el = el;
+        console.log(this);
+    }
+}

packages/artplayer-tool-thumbnail/src/index.scss

@@ -1,3 +1,3 @@
-.artplayerPluginDanmu {
+.artplayer-tool-thumbnail {
     display: flex;
 }