feat: Refactor worker.js to use dynamic function dispatch

packages/artplayer-plugin-danmuku/src/danmuku.js

@@ -514,7 +514,8 @@ export default class Danmuku {
                         const distance = clientWidth + danmu.$ref.clientWidth;
 
                         // 计算弹幕的top值
-                        const { top } = await this.postMessage({
+                        const { result: top } = await this.postMessage({
+                            type: 'getDanmuTop',
                             target: {
                                 mode: danmu.mode,
                                 height: danmu.$ref.clientHeight,

packages/artplayer-plugin-danmuku/src/worker.js

@@ -129,10 +129,14 @@ function getDanmuTop({ target, visibles, clientWidth, clientHeight, marginBottom
 
 onmessage = (event) => {
     const { data } = event;
-    if (!data.id) return;
-    const top = getDanmuTop(data);
+    if (!data.id || !data.type) return;
+
+    const fns = { getDanmuTop };
+    const fn = fns[data.type];
+    const result = fn(data);
+
     self.postMessage({
-        top,
+        result,
         id: data.id,
     });
 };