--description--

Given a video size, a unit for the video size, a hard drive capacity, and a unit for the hard drive, return the number of videos the hard drive can store using the following constraints:

• The unit for the video size can be bytes ("B"), kilobytes ("KB"), megabytes ("MB"), or gigabytes ("GB").
• If not given one of the video units above, return "Invalid video unit".
• The unit of the hard drive capacity can be gigabytes ("GB") or terabytes ("TB").
• If not given one of the hard drive units above, return "Invalid drive unit".
• Return the number of whole videos the drive can fit.
• Use the following conversions:

For example, given 500, "MB", 100, and "GB" as arguments, determine how many 500 MB videos can fit on a 100 GB hard drive.

--hints--

numberOfVideos(500, "MB", 100, "GB") should return 200.

assert.equal(numberOfVideos(500, "MB", 100, "GB"), 200);

numberOfVideos(1, "TB", 10, "TB") should return "Invalid video unit".

assert.equal(numberOfVideos(1, "TB", 10, "TB"), "Invalid video unit");

numberOfVideos(2000, "MB", 100000, "MB") should return "Invalid drive unit".

assert.equal(numberOfVideos(2000, "MB", 100000, "MB"), "Invalid drive unit");

numberOfVideos(500000, "KB", 2, "TB") should return 4000.

assert.equal(numberOfVideos(500000, "KB", 2, "TB"), 4000);

numberOfVideos(1.5, "GB", 2.2, "TB") should return 1466.

assert.equal(numberOfVideos(1.5, "GB", 2.2, "TB"), 1466);

--seed--

--seed-contents--

function numberOfVideos(videoSize, videoUnit, driveSize, driveUnit) {

  return videoSize;
}

--solutions--

function numberOfVideos(videoSize, videoUnit, driveSize, driveUnit) {
  const videoUnits = { "KB": 1000, "MB": 1000 * 1000, "GB": 1000 * 1000 * 1000 };
  const driveUnits = { "GB": 1000 * 1000 * 1000, "TB": 1000 * 1000 * 1000 * 1000 };

  if (!videoUnits[videoUnit]) return "Invalid video unit";
  if (!driveUnits[driveUnit]) return "Invalid drive unit";

  const videoBytes = videoSize * videoUnits[videoUnit];
  const driveBytes = driveSize * driveUnits[driveUnit];

  return Math.floor(driveBytes / videoBytes);
}