make connect/open/apenSet/disconnect return a promise, fixes #3622

lib/connection.js

@@ -9,7 +9,8 @@ var utils = require('./utils'),
     Collection = require(driver + '/collection'),
     STATES = require('./connectionstate'),
     MongooseError = require('./error'),
-    muri = require('muri');
+    muri = require('muri'),
+    PromiseProvider = require('./promise_provider');
 
 /*!
  * Protocol prefix regexp.
@@ -275,8 +276,18 @@ Connection.prototype.open = function(host, database, port, options, callback) {
   this.host = host;
   this.port = port;
 
-  this._open(callback);
-  return this;
+  var self = this;
+  var Promise = PromiseProvider.get();
+  return new Promise.ES6(function(resolve, reject) {
+    self._open(!!callback, function(error) {
+      callback && callback(error);
+      if (error) {
+        reject(error);
+        return;
+      }
+      resolve();
+    });
+  });
 };
 
 /**
@@ -405,8 +416,18 @@ Connection.prototype.openSet = function(uris, database, options, callback) {
 
   }
 
-  this._open(callback);
-  return this;
+  var self = this;
+  var Promise = PromiseProvider.get();
+  return new Promise.ES6(function(resolve, reject) {
+    self._open(!!callback, function(error) {
+      callback && callback(error);
+      if (error) {
+        reject(error);
+        return;
+      }
+      resolve();
+    });
+  });
 };
 
 /**
@@ -432,7 +453,7 @@ Connection.prototype.error = function(err, callback) {
  * @api private
  */
 
-Connection.prototype._open = function(callback) {
+Connection.prototype._open = function(emit, callback) {
   this.readyState = STATES.connecting;
   this._closeCalled = false;
 
@@ -449,7 +470,7 @@ Connection.prototype._open = function(callback) {
       if (self._hasOpened) {
         if (callback) callback(err);
       } else {
-        self.error(err, callback);
+        self.error(err, emit && callback);
       }
       return;
     }
@@ -508,6 +529,27 @@ Connection.prototype.onOpen = function(callback) {
  */
 
 Connection.prototype.close = function(callback) {
+  var self = this;
+  var Promise = PromiseProvider.get();
+  return new Promise.ES6(function(resolve, reject) {
+    self._close(function(error) {
+      callback && callback(error);
+      if (error) {
+        reject(error);
+        return;
+      }
+      resolve();
+    });
+  });
+};
+
+/**
+ * Handles closing the connection
+ *
+ * @param {Function} callback
+ * @api private
+ */
+Connection.prototype._close = function(callback) {
   var self = this;
   this._closeCalled = true;
 

lib/index.js

@@ -232,12 +232,11 @@ Mongoose.prototype.connect = function() {
   var conn = this.connection;
 
   if (rgxReplSet.test(arguments[0]) || checkReplicaSetInUri(arguments[0])) {
-    conn.openSet.apply(conn, arguments);
+    return conn.openSet.apply(conn, arguments);
   } else {
-    conn.open.apply(conn, arguments);
+    return conn.open.apply(conn, arguments);
   }
 
-  return this;
 };
 
 /**
@@ -249,24 +248,28 @@ Mongoose.prototype.connect = function() {
  */
 
 Mongoose.prototype.disconnect = function(fn) {
-  var count = this.connections.length,
-      error;
+  var error;
 
   this.connections.forEach(function(conn) {
     conn.close(function(err) {
-      if (error) return;
-
+      if (error) {
+        return;
+      }
       if (err) {
         error = err;
-        if (fn) return fn(err);
-        throw err;
       }
-
-      if (fn)
-        --count || fn();
     });
   });
-  return this;
+
+  var Promise = PromiseProvider.get();
+  return new Promise.ES6(function(resolve, reject) {
+    fn && fn(error);
+    if (error) {
+      reject(error);
+      return;
+    }
+    resolve();
+  });
 };
 
 /**

test/index.test.js

@@ -128,13 +128,11 @@ describe('mongoose module:', function() {
           cb(new Error('bam'));
         };
 
-        var failure = {};
-        try {
-          mong.disconnect();
-        } catch (err) {
-          failure = err;
-        }
-        assert.equal('bam', failure.message);
+        mong.disconnect()
+          .on('error', function (error) {
+            assert.equal('bam', error.message);
+          });
+
         done();
       });
     });