added factory pattern

Author: AnjanishKumar

pattern/factory-pattern.js

@@ -0,0 +1,51 @@
+function CarDoor( options ) {
+  this.color = options.color || 'red';
+  this.side = options.side || 'right';
+  this.hasPowerWindows = options.hasPowerWindows || true;
+}
+
+function CarSeat( options ) {
+  this.color = options.color || 'gray';
+  this.material = options.material || 'leather';
+  this.isReclinable = options.isReclinable || true;
+}
+
+function CarPartFactory() {}
+
+CarPartFactory.prototype.createPart = function createCarPart( options ) {
+  var parentClass = null;
+  
+  if( options.partType === 'door' ) {
+    parentClass = CarDoor;
+  } else if( options.partType === 'seat' ) {
+    parentClass = CarSeat;
+  }
+  
+  if( parentClass === null ) {
+    return false;
+  }
+  
+  return new parentClass( options );
+}
+
+// example usage
+var myPartFactory = new CarPartFactory();
+var seat = myPartFactory.createPart( {
+  partType : 'seat',
+  material : 'leather',
+  color : 'blue',
+  isReclinable : false
+} );
+
+// create a door with deault option
+var door = myPartFactory.createPart({partType:'door'});
+
+console.log( seat instanceof CarSeat ); // logs 'true
+
+//logs a CarSeat object with material "leather", color "blue", isReclinable "false"
+console.log( seat );
+
+console.log(door instanceof CarDoor); //logs 'true'
+//logs a CarDoor object with color "red", side "right", hasPowerWindows "true"
+console.log(door);
+