albumYear.js

  let yearAlbum  = {};
  let yearCount = new Map();
  for (let i = 0; i < data.length; i++) {
      for (let j = 0; j < data[i].bandAlbums.length; j++) {
          if (!yearCount.has(data[i].bandAlbums[j].albumYear)) {
              yearCount.set(`${data[i].bandAlbums[j].albumYear}`, 1)

          } else {
              yearCount.set(`${data[i].bandAlbums[j].albumYear}`, yearCount.get(`${data[i].bandAlbums[j].albumYear}`) + 1)
     }

      if (!(data[i].bandAlbums[j].albumYear in yearAlbum)) {
              let newAlbum = [];
              newAlbum.push(`${data[i].bandAlbums[j].albumName}`)
              yearAlbum[`${data[i].bandAlbums[j].albumYear}`] = newAlbum;
      }else{
              let albumArray = yearAlbum[`${data[i].bandAlbums[j].albumYear}`];
                  albumArray.push(`${data[i].bandAlbums[j].albumName}`)
              yearAlbum[`${data[i].bandAlbums[j].albumYear}`] = albumArray;
          }

      }
  }
  yearCount.delete('0000')
  // console.log(yearCount)
  console.log(yearAlbum);