1 files changed, 26 insertions, 0 deletions
diff --git a/node_modules/mongodb-core/lib/wireprotocol/shared.js b/node_modules/mongodb-core/lib/wireprotocol/shared.js
new file mode 100644
index 0000000..3a20f51
--- /dev/null
+++ b/node_modules/mongodb-core/lib/wireprotocol/shared.js
@@ -0,0 +1,26 @@
+"use strict"
+
+var ReadPreference = require('../topologies/read_preference');
+
+var getReadPreference = function(cmd, options) {
+  // Default to command version of the readPreference
+  var readPreference = cmd.readPreference || new ReadPreference('primary');
+  // If we have an option readPreference override the command one
+  if(options.readPreference) {
+    readPreference = options.readPreference;
+  }
+
+  if(typeof readPreference == 'string') {
+    readPreference = new ReadPreference(readPreference);
+  }
+
+  if(!(readPreference instanceof ReadPreference)) {
+    throw new MongoError('readPreference must be a ReadPreference instance');
+  }
+
+  return readPreference;
+}
+
+module.exports = {
+  getReadPreference: getReadPreference
+}