Remove null, undefined from doc in mongodb. [Terminal code]

remove-null.js

function getNullKeysRecursively(doc, keyName, nullKeys) {
  for (var item_property in doc) {
    // SKIP BASE-CLASS STUFF
    if (!doc.hasOwnProperty(item_property)) continue;
    // SKIP ID FIELD
    if (item_property === '_id') continue;

    // FULL KEY NAME (FOR SUB-DOCUMENTS)
    var fullKeyName;
    if (keyName) fullKeyName = keyName + '.' + item_property;
    else fullKeyName = item_property;

    // DEBUGGING
    // print("fullKeyName: " + fullKeyName);

    // NULL FIELDS - MODIFY THIS BLOCK TO ADD CONSTRAINTS
    if (doc[item_property] === null || doc[item_property] === undefined) nullKeys[fullKeyName] = 1;
    // RECURSE OBJECTS / ARRAYS
    else if (doc[item_property] instanceof Object || doc[item_property] instanceof Array)
      getNullKeysRecursively(doc[item_property], fullKeyName, nullKeys);
  }
}

/**
 * REMOVES ALL PROPERTIES WITH A VALUE OF 'NULL' OR 'UNDEFINED'.
 * TUNE THE 'LIMIT' VARIABLE TO YOUR MEMORY AVAILABILITY.
 * ONLY CLEANS DOCUMENTS THAT REQUIRE CLEANING, FOR EFFICIENCY.
 * USES bulkWrite FOR EFFICIENCY.
 *
 * @param collectionName
 */
function removeNulls(collectionName) {
  var coll = db.getCollection(collectionName);
  const data = coll.find({});
  var arrBulkOps = [];

  data.forEach(function(item_doc) {
    var nullKeys = {};
    getNullKeysRecursively(item_doc, null, nullKeys);

    // ONLY UPDATE MODIFIED DOCUMENTS
    if (Object.keys(nullKeys).length > 0) {
      console.log('..... ', item_doc._id);
      // UNSET INDIVIDUAL FIELDS, RATHER THAN REWRITE THE ENTIRE DOC
      arrBulkOps.push({
        updateOne: {
          filter: { _id: item_doc._id },
          update: { $unset: nullKeys }
        }
      });
    } else {
      console.log('---> ', item_doc._id);
    }
  });

  coll.bulkWrite(arrBulkOps, { ordered: false });
}

// GO GO GO
removeNulls('Resource');