Show each collection size in MongoDB

mongodb-collections-sizes.js

var getReadableFileSizeString = function(fileSizeInBytes) {
  var i = -1;
  var byteUnits = [' kB', ' MB', ' GB', ' TB', 'PB', 'EB', 'ZB', 'YB'];
  do {
    fileSizeInBytes = fileSizeInBytes / 1024;
    i++;
  } while (fileSizeInBytes > 1024);
  return Math.max(fileSizeInBytes, 0.1).toFixed(1) + byteUnits[i];
};

printCollectionSizes = function () {
  var collectionNames = db.getCollectionNames();
  var stats = [];
  collectionNames.forEach(function (n) {
    stats.push(db.getCollection(n).stats());
  });
  stats = stats.sort(function(a, b) { return b.size - a.size; });
  for (var c in stats) {
    print(stats[c]['ns'] + ": " + getReadableFileSizeString(stats[c]['size']) + " (" + getReadableFileSizeString(stats[c]['storageSize']) + ")" + " (Indexes: " + getReadableFileSizeString(stats[c]['totalIndexSize']) + ")");
  }
}

// Copy-paste code above as it is to MongoDB CLI Shell
// Hit [return]/[enter] key to make sure last line passed through
// type-in `printCollectionSizes()`
//
// OUTPUT:
// Collection_Name Records_Size (Actual_Storage_Size_On_FS) (Indexes: Indexes_Size_In_Memory)