Frames to Timecode in JavaScript, Timecode to Frames in Javascript

framesTimecodeConverter.js

const FRAME_RATE = 24;

const framesToTimecode = (timeInFrames) => {
  const numOfFramesPerMin = FRAME_RATE * 60;
  const hours = Math.floor(timeInFrames / (numOfFramesPerMin * 60));
  const minutes = Math.floor(timeInFrames / numOfFramesPerMin) % 60;
  const seconds = Math.floor((timeInFrames % numOfFramesPerMin) / FRAME_RATE);
  const frames = Math.floor((timeInFrames % numOfFramesPerMin) % FRAME_RATE);

  const timecode = {
    hours: hours,
    minutes: minutes,
    seconds: seconds,
    frames: frames,
  };

  return timecode;

  // Logic for parsing:
  
  // Hours  : Divide total num of frames by number of frames in one hour.
  // Minutes: Divide the total num of frames by number of frames in one minute.
  //          This will give you the total number of minutes (for ex, it'll give 122 if time is 2h 2min).
  //          We don't want the hours, we just want extra mins, so modulo it by 60.
  // Seconds: timeInFrames % numOfFramesPerMin removes all full minutes and returns the number of remaining frames.
  //          Divide that by the frame rate to convert to seconds.
  // Frames : timeInFrames % numOfFramesPerMin removes all full minutes and returns the number of remaining frames.
  //          Take that number and modulo it by the frame rate to remove all full seconds, which leaves us with the remaining # of frames
};

const timecodeToFrames = (timecode) => {
  // "timecode" should be a string of the format "hh:mm:ss:fr"
  let [hours, minutes, seconds, frames] = timeString.split(':').map((x) => Number(x));

  return (hours * FRAME_RATE * 60 * 60) + (minutes * FRAME_RATE * 60) + (seconds * FRAME_RATE) + frames;
}