1 files changed, 100 insertions, 0 deletions
diff --git a/javascript/videojs/src/js/tracks/text-track-list-converter.js b/javascript/videojs/src/js/tracks/text-track-list-converter.js
new file mode 100644
index 0000000..16953ef
--- /dev/null
+++ b/javascript/videojs/src/js/tracks/text-track-list-converter.js
@@ -0,0 +1,100 @@
+/**
+ * @file text-track-list-converter.js Utilities for capturing text track state and
+ * re-creating tracks based on a capture.
+ *
+ * @module text-track-list-converter
+ */
+
+/** @import Tech from '../tech/tech' */
+
+/**
+ * Examine a single {@link TextTrack} and return a JSON-compatible javascript object that
+ * represents the {@link TextTrack}'s state.
+ *
+ * @param {TextTrack} track
+ *        The text track to query.
+ *
+ * @return {Object}
+ *         A serializable javascript representation of the TextTrack.
+ * @private
+ */
+const trackToJson = function(track) {
+  const ret = [
+    'kind', 'label', 'language', 'id',
+    'inBandMetadataTrackDispatchType', 'mode', 'src'
+  ].reduce((acc, prop, i) => {
+
+    if (track[prop]) {
+      acc[prop] = track[prop];
+    }
+
+    return acc;
+  }, {
+    cues: track.cues && Array.prototype.map.call(track.cues, function(cue) {
+      return {
+        startTime: cue.startTime,
+        endTime: cue.endTime,
+        text: cue.text,
+        id: cue.id
+      };
+    })
+  });
+
+  return ret;
+};
+
+/**
+ * Examine a {@link Tech} and return a JSON-compatible javascript array that represents the
+ * state of all {@link TextTrack}s currently configured. The return array is compatible with
+ * {@link text-track-list-converter:jsonToTextTracks}.
+ *
+ * @param {Tech} tech
+ *        The tech object to query
+ *
+ * @return {Array}
+ *         A serializable javascript representation of the {@link Tech}s
+ *         {@link TextTrackList}.
+ */
+const textTracksToJson = function(tech) {
+
+  const trackEls = tech.$$('track');
+
+  const trackObjs = Array.prototype.map.call(trackEls, (t) => t.track);
+  const tracks = Array.prototype.map.call(trackEls, function(trackEl) {
+    const json = trackToJson(trackEl.track);
+
+    if (trackEl.src) {
+      json.src = trackEl.src;
+    }
+    return json;
+  });
+
+  return tracks.concat(Array.prototype.filter.call(tech.textTracks(), function(track) {
+    return trackObjs.indexOf(track) === -1;
+  }).map(trackToJson));
+};
+
+/**
+ * Create a set of remote {@link TextTrack}s on a {@link Tech} based on an array of javascript
+ * object {@link TextTrack} representations.
+ *
+ * @param {Array} json
+ *        An array of `TextTrack` representation objects, like those that would be
+ *        produced by `textTracksToJson`.
+ *
+ * @param {Tech} tech
+ *        The `Tech` to create the `TextTrack`s on.
+ */
+const jsonToTextTracks = function(json, tech) {
+  json.forEach(function(track) {
+    const addedTrack = tech.addRemoteTextTrack(track).track;
+
+    if (!track.src && track.cues) {
+      track.cues.forEach((cue) => addedTrack.addCue(cue));
+    }
+  });
+
+  return tech.textTracks();
+};
+
+export default {textTracksToJson, jsonToTextTracks, trackToJson};