Refactoring day1

node_modules/mongodb/lib/change_stream.js

@@ -169,6 +169,7 @@ class ChangeStream extends EventEmitter {
   /**
    * Is the change stream closed
    * @method ChangeStream.prototype.isClosed
+   * @param  {boolean} [checkCursor=true] also check if the underlying cursor is closed
    * @return {boolean}
    */
   isClosed() {
@@ -325,8 +326,8 @@ class ChangeStreamCursor extends Cursor {
 
   _initializeCursor(callback) {
     super._initializeCursor((err, result) => {
-      if (err || result == null) {
-        callback(err, result);
+      if (err) {
+        callback(err);
         return;
       }
 
@@ -482,11 +483,6 @@ function waitForTopologyConnected(topology, options, callback) {
 function processNewChange(changeStream, change, callback) {
   const cursor = changeStream.cursor;
 
-  // a null change means the cursor has been notified, implicitly closing the change stream
-  if (change == null) {
-    changeStream.closed = true;
-  }
-
   if (changeStream.closed) {
     if (callback) callback(new MongoError('ChangeStream is closed'));
     return;