Add handling for password only connections (mqttjs#1685)

src/lib/connect/index.ts

@@ -42,7 +42,11 @@ function parseAuthOptions(opts: IClientOptions) {
 		if (matches) {
 			opts.username = matches[1]
 			opts.password = matches[2]
+		} else if (opts.auth.startsWith(':')) {
+			// Password only, no username provided
+			opts.password = opts.auth.slice(1)
 		} else {
+			// Username only, no password provided
 			opts.username = opts.auth
 		}
 	}

test/mqtt.ts

@@ -35,6 +35,14 @@ describe('mqtt', () => {
 			c.end((err) => done(err))
 		})
 
+		it('should return an MqttClient with password option set', function _test(t, done) {
+			const c = mqtt.connect('mqtt://:pass@localhost:1883')
+
+			c.should.be.instanceOf(mqtt.MqttClient)
+			c.options.should.have.property('password', 'pass')
+			c.end((err) => done(err))
+		})
+
 		it('should return an MqttClient with username and password options set', function _test(t, done) {
 			const c = mqtt.connect('mqtt://user@localhost:1883')