Refactoring, comments & overall improvements

modules/music/lib/fetch/extractors.ts

@@ -0,0 +1,64 @@
+import { DlpDump, dlpExtractorKey, DlpInfo } from "$mlib/types.js";
+
+export const dlpExtractorsValues = ["Youtube", "Soundcloud"] as const;
+
+/**
+ * Defines structure for an extractor that will be called by dlpInfo.
+ *
+ * For example:
+ *
+ * @see the {@link youtubeExtractor | youtubeExtractor(...) } function
+ */
+type dlpExtractor = (arg0: DlpDump, arg1: (arg0: string) => Promise<DlpInfo>) => Promise<DlpInfo>;
+
+/**
+ * Resolves data that was extracted by dlp (depending on extractor_key).
+ *
+ * @returns DlpInfo generated from dump provided
+ *
+ * @param dump - Parsed dlp output
+ * @param dlpInfo - Function to call if any other information needed
+ * (will recurcively call next extractor after its run)
+ */
+const youtubeExtractor: dlpExtractor = async (dump, dlpInfo) => {
+    if (dump.id && dump.title && dump.duration) {
+        const result = {
+            url: `https://www.youtube.com/watch?v=${dump.id}`,
+            title: dump.title,
+            thumbnail: `https://img.youtube.com/vi/${dump.id}/default.jpg`,
+            duration: dump.duration
+        };
+
+        return [result];
+    }
+
+    return await dlpInfo(dump.original_url);
+};
+
+/**
+ * {@inheritdoc youtubeExtractor}
+ */
+const soundcloudExtractor: dlpExtractor = async (dump, dlpInfo) => {
+    if (dump.title && dump.duration && dump.thumbnail) {
+        const result = {
+            url: dump.webpage_url ?? dump.original_url,
+            title: dump.title,
+            thumbnail: dump.thumbnail,
+            duration: dump.duration
+        };
+
+        return [result];
+    }
+
+    return await dlpInfo(dump.original_url);
+};
+
+/**
+ * DlpDump extractor_key values mapped to corresponding extractor.
+ */
+const extractors: Record<dlpExtractorKey, dlpExtractor> = {
+    Youtube: youtubeExtractor,
+    Soundcloud: soundcloudExtractor
+};
+
+export default extractors;