Refactor subtitle loading function

docs/uncompiled/artplayer-plugin-multiple-subtitles/index.js

@@ -158,7 +158,7 @@ function unescape(str) {
     const reg = new RegExp(`(${Object.keys(map).join("|")})`, "g");
     return str.replace(reg, (tag)=>map[tag] || tag);
 }
-async function loadSubtitleAsVtt(option, art) {
+async function loadVtt(option, art) {
     const { getExt, srtToVtt, assToVtt } = art.constructor.utils;
     const response = await fetch(option.url);
     const buffer = await response.arrayBuffer();
@@ -193,14 +193,16 @@ function mergeTrees(trees, subtitles) {
     }
     return result;
 }
+const all = "_ALL_";
 function artplayerPluginMultipleSubtitles({ subtitles, onMerge = ()=>null }) {
     return async (art)=>{
-        const vtts = await Promise.all(subtitles.map((option)=>loadSubtitleAsVtt(option, art)));
         const parser = new (0, _parser.WebVTTParser)();
-        const trees = vtts.map((vtt)=>parser.parse(vtt, "metadata"));
         const seri = new (0, _parser.WebVTTSerializer)();
+        const vtts = await Promise.all(subtitles.map((option)=>loadVtt(option, art)));
+        const trees = vtts.map((vtt)=>parser.parse(vtt, "metadata"));
         const tree = onMerge(trees, subtitles) || mergeTrees(trees, subtitles);
-        if (tree?.cues?.length) {
+        function setTree(tree) {
+            if (!tree?.cues) return;
             const vtt = seri.serialize(tree.cues);
             const url = URL.createObjectURL(new Blob([
                 vtt
@@ -214,12 +216,34 @@ function artplayerPluginMultipleSubtitles({ subtitles, onMerge = ()=>null }) {
                 type: "vtt",
                 onVttLoad: unescape
             });
-        } else throw new Error("No subtitle found");
+        }
+        setTree(tree);
+        let _track = all;
+        return {
+            name: "multipleSubtitles",
+            get track () {
+                return _track;
+            },
+            set track (name){
+                if (name === all || name === "") {
+                    _track = all;
+                    setTree(tree);
+                } else {
+                    const index = subtitles.findIndex((item)=>item.name === name);
+                    if (index === -1) throw new Error(`The subtitle "${name}" is not found`);
+                    else {
+                        _track = name;
+                        setTree(trees[index]);
+                    }
+                }
+            }
+        };
     };
 }
 artplayerPluginMultipleSubtitles.env = "development";
 artplayerPluginMultipleSubtitles.version = "1.0.0";
 artplayerPluginMultipleSubtitles.build = "2023-11-24 00:15:21";
+artplayerPluginMultipleSubtitles.all = all;
 artplayerPluginMultipleSubtitles.WebVTTParser = (0, _parser.WebVTTParser);
 artplayerPluginMultipleSubtitles.WebVTTSerializer = (0, _parser.WebVTTSerializer);
 if (typeof window !== "undefined") window["artplayerPluginMultipleSubtitles"] = artplayerPluginMultipleSubtitles;