Creating things from scratch can be tough, especially when you’re building a website or app. Luckily, design patterns are like blueprints for writing code. They’re tried-and-true solutions to common problems, helping you write cleaner, more organized code. In this lesson, we’ll dive into creational design patterns—the ones that focus on how you create objects. Using these patterns will make your code more readable and easier to maintain. Plus, you won’t have to repeat yourself! 🚀

The Factory Function Pattern

Imagine you have a cookie-making machine. Instead of building a whole new machine every time you want a cookie, you just press a button, and the machine makes one for you. A factory function works the same way. It’s a simple function that returns an object.

Factory functions are great because they don’t need the new keyword, which can sometimes be confusing. For example, a popular library called jQuery uses factory functions.

You can also use this pattern to create private properties and methods. Think of private stuff as the secret recipe for your cookies—no one outside the factory needs to know the details! You do this by using a closure, which is like a secret box that keeps some variables and functions hidden from the outside world.

Composition over Inheritance

Have you ever tried to give a cat a dog’s behaviors, like fetching a ball? 🐕 It doesn’t quite work, right? This is similar to a problem in programming called inheritance, where an object gets all the traits of its parent, even the ones it doesn’t need.

A better way is composition, where you build objects by giving them only the behaviors they need. Instead of inheriting from one giant “animal” class, you’d create separate “behavior factories” for things like canTalk or canFly. Then, you “compose” an object by combining these behaviors. This is much more flexible and avoids unnecessary code!

The Module Pattern

Sometimes, you want to keep parts of your code private while exposing only a public “interface.” The Module Pattern is perfect for this. It uses a special kind of function called an Immediately Invoked Function Expression (IIFE). This function runs as soon as it’s defined and creates a private scope.

Imagine it like a clubhouse with a secret password. All the private members and data are inside, and the only way to access them is through the public methods you choose to expose. The Revealing Module Pattern is a variation where you list all your private members and then simply return an object that “reveals” which ones are public.

The Prototype Pattern

JavaScript is a bit different from other languages because it uses prototypal inheritance. This means objects can inherit directly from other objects without needing a class. The Prototype Pattern takes advantage of this.

Think of it like a blueprint. You create an object that serves as the blueprint, and any new objects you create from it will share the same methods. This is super efficient because you’re not creating a new copy of the same function for every object. Instead, all your objects share the same single copy.

The Singleton Pattern

The Singleton Pattern is all about being unique. It makes sure that only one instance of a specific object can ever exist. For example, if you have a settings panel for your app, you only ever need one of them.

This pattern uses a clever trick with a closure to store the single instance. The first time you ask for the object, it’s created. Every time after that, you get the exact same object back.

The Abstract Factory Pattern

The Abstract Factory Pattern is for when you need to create different types of objects without specifying their exact “class.”

Imagine a car factory that can build different types of vehicles. You don’t need to know the specific details of how to build a car versus a truck. You just call a method like createVehicle and tell it what type you want. The factory then takes care of the rest, giving you a car or a truck as needed.

Fill in the Blanks!

  1. A factory function is a function that returns an ____.
  2. The “Don’t Repeat Yourself” principle is often shortened to the acronym ____.
  3. The Module Pattern uses a special function called an ____ to create a private scope.
  4. Instead of inheritance, the composition pattern prefers to combine different ____ to create an object.
  5. The Prototype Pattern works because objects created from a blueprint share the same ____.
  6. A Singleton pattern ensures that only ____ object of a certain type can ever be created.
  7. The Revealing Module Pattern is a variation where you ____ the public API.
  8. Factory functions don’t require the use of the ____ keyword.
  9. The Abstract Factory Pattern helps you create different types of objects without knowing their exact ____.
  10. Encapsulating private properties in a factory function is done using a ____.
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