refactor(sdam): null => undefined

Author: mbroadst

lib/core/sdam/topology.js

@@ -272,7 +272,6 @@ class Topology extends EventEmitter {
 
     translateReadPreference(options);
     const readPreference = options.readPreference || ReadPreference.primary;
-
     this.selectServer(readPreferenceServerSelector(readPreference), options, (err, server) => {
       if (err) {
         stateTransition(this, STATE_CLOSED);
@@ -420,7 +419,7 @@ class Topology extends EventEmitter {
     const transaction = session && session.transaction;
 
     if (isSharded && transaction && transaction.server) {
-      callback(null, transaction.server);
+      callback(undefined, transaction.server);
       return;
     }
 
@@ -434,14 +433,14 @@ class Topology extends EventEmitter {
       options.serverSelectionTimeoutMS,
       process.hrtime(),
       (err, servers) => {
-        if (err) return callback(err, null);
+        if (err) return callback(err);
 
         const selectedServer = randomSelection(servers);
         if (isSharded && transaction && transaction.isActive) {
           transaction.pinServer(selectedServer);
         }
 
-        callback(null, selectedServer);
+        callback(undefined, selectedServer);
       }
     );
   }
@@ -564,11 +563,11 @@ class Topology extends EventEmitter {
 
   auth(credentials, callback) {
     if (typeof credentials === 'function') (callback = credentials), (credentials = null);
-    if (typeof callback === 'function') callback(null, true);
+    if (typeof callback === 'function') callback(undefined, true);
   }
 
   logout(callback) {
-    if (typeof callback === 'function') callback(null, true);
+    if (typeof callback === 'function') callback(undefined, true);
   }
 
   // Basic operation support. Eventually this should be moved into command construction
@@ -648,7 +647,7 @@ class Topology extends EventEmitter {
 
     this.selectServer(readPreferenceServerSelector(readPreference), options, (err, server) => {
       if (err) {
-        callback(err, null);
+        callback(err);
         return;
       }
 
@@ -661,7 +660,7 @@ class Topology extends EventEmitter {
         isWriteCommand(cmd);
 
       const cb = (err, result) => {
-        if (!err) return callback(null, result);
+        if (!err) return callback(undefined, result);
         if (!isRetryableError(err)) {
           return callback(err);
         }