Also known as Dependents or Publish-Subscribe, the Observer pattern helps us create decoupled components and modules. It improves the testability, composition, and scalability of our applications. In this post, I’m going to show you some concepts around the Observer pattern, how it works, and a practical example.

What is Observer?

The authors of the book Design Patterns: Elements of Reusable Object-Oriented Software defines Observer Pattern as:

Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

We can think of the Observer pattern as a communication channel between two different modules or…

Singleton is one of the most used design patterns in software development. In this post, we will learn how to implement this pattern in the context of web development using TypeScript.

What is Singleton?

The authors of the book Design Patterns: Elements of Reusable Object-Oriented Software defines Singleton Pattern as:

A singleton class is a class that has a single object and that unique object constitutes a global facility for all clients.

Basically, the singleton pattern forces you to get an instance of the class via a class method or a getter. …

The AC-3 algorithm simplifies a constraint satisfaction problem using the constraints to prune out values from the variables domain.

In this article, we will see how the AC-3 algorithm works and the implementation in Python.

How It Works

We can represent the AC-3 algorithm in 3 steps:

1. Get all the constraints and turn each one into two arcs. For example:
   𝐴 > 𝐵 becomes 𝐴 > 𝐵 and 𝐵 < 𝐴.
2. Add all the arcs to a queue.
3. Repeat until the queue is empty:
   3.1. Take the first arc (𝑥, 𝑦), off the queue (dequeue).
   3.2. For every value in the 𝑥 domain, there must…

In my last post, I showed you how to configure, develop, and generate a WASM file via GoLang. In this post, I will show you the best practices and how to use these strategies in a real modern web project.

Why Reduce the Binary File Size

If you already generate a web assembly binary file using Go, you’ve probably noticed how big the file size is. As we load this binary file on a web page, it will affect the load of other assets on the page. It can affect Time to Interactive (TTI) as well. TTI measures how long it takes a page to become…

Why Do We Need WebAssembly?

Today web and mobile applications are the primary vehicles for providing software solutions to users around the world. Applications that we had only in desktop apps today are available for browsers like graphics, photo and video editors; music and video players; and so on.

To use a sophisticated tool in a web browser, sometimes you need to use a specific language, not JavaScript. We have to use a language that provides an easy way to build that type of application. …

The goal of linear programming is to minimize a cost function that has some number of variables (x₁, x₂, x₃) all the way up to x𝑛. Those variables are involved in things that I want to know the values to, and they might be multiplied by a coefficient and then added together.

With linear programming, we are just dealing with linear equations, so we’re not going to square or cube anything.

Also, we’ll have some linear constraints:

• a₁x₁ + a₂x₂ + … + a𝑛x𝑛 ≤ b
• a₁x₁ + a₂x₂ + … + a𝑛x𝑛 = b

With the following bound for…

When you have a Next.js application you probably use Styled JSX to write the style of your components. It is because Next.js includes Styled JSX by default in your project. If this is your case or you’re just using Styled JSX by yourself and you want to implement a Dark/Light mode switch on your website this article is for you.

We will implement a simple theme toggle (Dark <-> Light ) using some techniques with this CSS-in-JS library and JavaScript in four steps.

First Step: Defining Your Themes

The first step is to choose the right colors for your dark and light themes. Defining the…

The Simulated Annealing algorithm is commonly used when we’re stuck trying to optimize solutions that generate local minimum or local maximum solutions, for example, the Hill-Climbing algorithm. So we use the Simulated Annealing algorithm to have a better solution to find the global maximum or global minimum.

Why Simulated Annealing?

It’s called Simulated Annealing because it’s modeling after a real physical process of annealing something like a metal. When you heat a particular metal, there’s a lot of energy there, and you can move things around quite systematically. But over time, as the system cools down, it eventually settles into a final position.

…