How to use the mongodb-core.ReadPreference.PRIMARY function in mongodb-core

Db.prototype.dropCollection = function(name, options, callback) {
  if (typeof options === 'function') (callback = options), (options = {});
  options = options || {};

  // Command to execute
  const cmd = { drop: name };

  // Decorate with write concern
  applyWriteConcern(cmd, { db: this }, options);

  // options
  const opts = Object.assign({}, this.s.options, { readPreference: ReadPreference.PRIMARY });
  if (options.session) opts.session = options.session;

  return executeOperation(this.s.topology, dropCollection, [this, cmd, opts, callback]);
};

const capabilities = db.s.topology.capabilities();

  // Did the user pass in a collation, check if our write server supports it
  if (indexes[0].collation && capabilities && !capabilities.commandsTakeCollation) {
    // Create a new error
    const error = new MongoError('server/primary/mongos does not support collation');
    error.code = 67;
    // Return the error
    return callback(error);
  }

  // Create command, apply write concern to command
  const cmd = applyWriteConcern({ createIndexes: name, indexes }, { db }, options);

  // ReadPreference primary
  options.readPreference = ReadPreference.PRIMARY;

  // Build the command
  executeCommand(db, cmd, options, (err, result) => {
    if (err) return handleCallback(callback, err, null);
    if (result.ok === 0) return handleCallback(callback, toError(result), null);
    // Return the indexName for backward compatibility
    handleCallback(callback, null, indexName);
  });
}

if (indexes[0].collation && capabilities && !capabilities.commandsTakeCollation) {
    // Create a new error
    var error = new MongoError(f('server/primary/mongos does not support collation'));
    error.code = 67;
    // Return the error
    return callback(error);
  }

  // Create command, apply write concern to command
  var cmd = writeConcern({ createIndexes: name, indexes: indexes }, self, options);

  // Decorate command with writeConcern if supported
  decorateWithWriteConcern(cmd, self, options);

  // ReadPreference primary
  options.readPreference = ReadPreference.PRIMARY;

  // Build the command
  self.command(cmd, options, function(err, result) {
    if (err) return handleCallback(callback, err, null);
    if (result.ok === 0) return handleCallback(callback, toError(result), null);
    // Return the indexName for backward compatibility
    handleCallback(callback, null, indexName);
  });
};

Collection.prototype.dropIndex = function(indexName, options, callback) {
  const args = Array.prototype.slice.call(arguments, 1);
  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;

  options = args.length ? args.shift() || {} : {};
  // Run only against primary
  options.readPreference = ReadPreference.PRIMARY;

  return executeOperation(this.s.topology, dropIndex, [this, indexName, options, callback]);
};

Collection.prototype.rename = function(newName, options, callback) {
  if (typeof options === 'function') (callback = options), (options = {});
  options = Object.assign({}, options, { readPreference: ReadPreference.PRIMARY });

  return executeOperation(this.s.topology, rename, [this, newName, options, callback]);
};

Collection.prototype.rename = function(newName, options, callback) {
  if (typeof options === 'function') (callback = options), (options = {});
  options = Object.assign({}, options, { readPreference: ReadPreference.PRIMARY });

  return executeOperation(this.s.topology, rename, [this, newName, options, callback]);
};

Collection.prototype.rename = function(newName, options, callback) {
  if (typeof options === 'function') (callback = options), (options = {});
  options = Object.assign({}, options, { readPreference: ReadPreference.PRIMARY });

  return executeOperation(this.s.topology, rename, [this, newName, options, callback]);
};