Cleanup

node_modules/mongoose/lib/drivers/node-mongodb-native/connection.js

@@ -6,6 +6,8 @@
 
 const MongooseConnection = require('../../connection');
 const STATES = require('../../connectionstate');
+const immediate = require('../../helpers/immediate');
+const setTimeout = require('../../helpers/timers').setTimeout;
 
 /**
  * A [node-mongodb-native](https://github.com/mongodb/node-mongodb-native) connection implementation.
@@ -38,16 +40,20 @@ NativeConnection.prototype.__proto__ = MongooseConnection.prototype;
  * Returns a new connection object, with the new db. If you set the `useCache`
  * option, `useDb()` will cache connections by `name`.
  *
+ * **Note:** Calling `close()` on a `useDb()` connection will close the base connection as well.
+ *
  * @param {String} name The database name
  * @param {Object} [options]
  * @param {Boolean} [options.useCache=false] If true, cache results so calling `useDb()` multiple times with the same name only creates 1 connection object.
+ * @param {Boolean} [options.noListener=false] If true, the new connection object won't listen to any events on the base connection. This is better for memory usage in cases where you're calling `useDb()` for every request.
  * @return {Connection} New Connection Object
  * @api public
  */
 
 NativeConnection.prototype.useDb = function(name, options) {
   // Return immediately if cached
-  if (options && options.useCache && this.relatedDbs[name]) {
+  options = options || {};
+  if (options.useCache && this.relatedDbs[name]) {
     return this.relatedDbs[name];
   }
 
@@ -58,7 +64,7 @@ NativeConnection.prototype.useDb = function(name, options) {
   newConn.collections = {};
   newConn.models = {};
   newConn.replica = this.replica;
-  newConn.config = Object.assign({}, this.base.connection.config, newConn.config);
+  newConn.config = Object.assign({}, this.config, newConn.config);
   newConn.name = this.name;
   newConn.options = this.options;
   newConn._readyState = this._readyState;
@@ -90,16 +96,24 @@ NativeConnection.prototype.useDb = function(name, options) {
 
   function wireup() {
     newConn.client = _this.client;
-    newConn.db = _this.client.db(name);
+    const _opts = {};
+    if (options.hasOwnProperty('noListener')) {
+      _opts.noListener = options.noListener;
+    }
+    newConn.db = _this.client.db(name, _opts);
     newConn.onOpen();
     // setup the events appropriately
-    listen(newConn);
+    if (options.noListener !== true) {
+      listen(newConn);
+    }
   }
 
   newConn.name = name;
 
   // push onto the otherDbs stack, this is used when state changes
-  this.otherDbs.push(newConn);
+  if (options.noListener !== true) {
+    this.otherDbs.push(newConn);
+  }
   newConn.otherDbs.push(this);
 
   // push onto the relatedDbs cache, this is used when state changes
@@ -116,13 +130,16 @@ NativeConnection.prototype.useDb = function(name, options) {
  */
 
 function listen(conn) {
-  if (conn.db._listening) {
+  if (conn._listening) {
     return;
   }
-  conn.db._listening = true;
+  conn._listening = true;
 
-  conn.db.on('close', function(force) {
-    if (conn._closeCalled) return;
+  conn.client.on('close', function(force) {
+    if (conn._closeCalled) {
+      return;
+    }
+    conn._closeCalled = conn.client._closeCalled;
 
     // the driver never emits an `open` event. auto_reconnect still
     // emits a `close` event but since we never get another
@@ -134,26 +151,30 @@ function listen(conn) {
     }
     conn.onClose(force);
   });
-  conn.db.on('error', function(err) {
+  conn.client.on('error', function(err) {
     conn.emit('error', err);
   });
-  conn.db.on('reconnect', function() {
-    conn.readyState = STATES.connected;
-    conn.emit('reconnect');
-    conn.emit('reconnected');
-    conn.onOpen();
-  });
-  conn.db.on('timeout', function(err) {
-    conn.emit('timeout', err);
-  });
-  conn.db.on('open', function(err, db) {
-    if (STATES.disconnected === conn.readyState && db && db.databaseName) {
+
+  if (!conn.client.s.options.useUnifiedTopology) {
+    conn.db.on('reconnect', function() {
       conn.readyState = STATES.connected;
       conn.emit('reconnect');
       conn.emit('reconnected');
-    }
+      conn.onOpen();
+    });
+    conn.db.on('open', function(err, db) {
+      if (STATES.disconnected === conn.readyState && db && db.databaseName) {
+        conn.readyState = STATES.connected;
+        conn.emit('reconnect');
+        conn.emit('reconnected');
+      }
+    });
+  }
+
+  conn.client.on('timeout', function(err) {
+    conn.emit('timeout', err);
   });
-  conn.db.on('parseError', function(err) {
+  conn.client.on('parseError', function(err) {
     conn.emit('parseError', err);
   });
 }
@@ -168,6 +189,11 @@ function listen(conn) {
  */
 
 NativeConnection.prototype.doClose = function(force, fn) {
+  if (this.client == null) {
+    immediate(() => fn());
+    return this;
+  }
+
   this.client.close(force, (err, res) => {
     // Defer because the driver will wait at least 1ms before finishing closing
     // the pool, see https://github.com/mongodb-js/mongodb-core/blob/a8f8e4ce41936babc3b9112bf42d609779f03b39/lib/connection/pool.js#L1026-L1030.