chore: first commit

src/index.js

@@ -0,0 +1,60 @@
+/* @flow */
+
+import he from 'he';
+import axios from 'axios';
+import { find } from 'lodash';
+
+export async function getSubtitles({
+  videoID,
+  lang = 'en',
+}: {
+  videoID: string,
+  lang: 'en',
+}) {
+  const { data } = await axios.get(
+    `https://youtube.com/get_video_info?video_id=${videoID}`
+  );
+
+  const decodedData = decodeURIComponent(data);
+
+  // * ensure we have access to captions data
+  if (!decodedData.includes('captionTracks'))
+    throw new Error(`Could not find captions for video: ${videoID}`);
+
+  const regex = /({"captionTracks":.*isTranslatable":(true|false)}])/;
+  const [match] = regex.exec(decodedData);
+  const { captionTracks } = JSON.parse(`${match}}`);
+
+  const subtitle =
+    find(captionTracks, { vssId: `.${lang}` }) ||
+    find(captionTracks, { vssId: `a.${lang}` });
+
+  // * ensure we have found the correct subtitle lang
+  if (!subtitle || (subtitle && !subtitle.baseUrl))
+    throw new Error(`Could not find ${lang} captions for ${videoID}`);
+
+  const { data: transcript } = await axios.get(subtitle.baseUrl);
+  const lines = transcript
+    .replace('<?xml version="1.0" encoding="utf-8" ?><transcript>', '')
+    .replace('</transcript>', '')
+    .split('</text>')
+    .filter(line => line && line.trim())
+    .map(line => {
+      const startRegex = /start="([\d.]+)"/;
+      const durRegex = /dur="([\d.]+)"/;
+
+      const [, start] = startRegex.exec(line);
+      const [, dur] = durRegex.exec(line);
+
+      const htmlText = line
+        .replace(/<text.+>/, '')
+        .replace(/&amp;/gi, '&')
+        .replace(/<\/?[^>]+(>|$)/g, '');
+
+      const text = he.decode(htmlText);
+
+      return { start, dur, text };
+    });
+
+  return lines;
+}