The addCue() method of the TextTrack interface adds a new cue to the list of cues.
addCue(cue)cueA TextTrackCue.
Note: The TextTrackCue interface is an abstract class used as the parent for other cue interfaces such as VTTCue. Therefore, when adding a cue you will be using one of the cue types that inherit from TextTrackCue.
Undefined.
InvalidStateError DOMExceptionThrown if the rules for this TextTrackList do not match those that are appropriate for the incoming TextTrackCue.
In the following example two cues are added to a video text track using addCue().
let video = document.querySelector("video");
let track = video.addTextTrack("captions", "Captions", "en");
track.mode = "showing";
track.addCue(new VTTCue(0, 0.9, "Hildy!"));
track.addCue(new VTTCue(1, 1.4, "How are you?"));