3 var ReadPreference = require('../topologies/read_preference');
5 var getReadPreference = function(cmd, options) {
6 // Default to command version of the readPreference
7 var readPreference = cmd.readPreference || new ReadPreference('primary');
8 // If we have an option readPreference override the command one
9 if(options.readPreference) {
10 readPreference = options.readPreference;
13 if(typeof readPreference == 'string') {
14 readPreference = new ReadPreference(readPreference);
17 if(!(readPreference instanceof ReadPreference)) {
18 throw new MongoError('readPreference must be a ReadPreference instance');
21 return readPreference;
25 getReadPreference: getReadPreference