In this article, we’re going to focus on how to refactor the legacy codebase, so that it’s testable again (no framework for Dependency Injection needed) — Background Probably the majority of software developers know terms such as Unit Testing and TDD very well. Developers staffed on projects work hard and do their best to deliver solutions that satisfy business requirements. However, sometimes, due to unexpected difficulties (underestimated user story/changing requirements/upcoming deadline/too small team/lack of knowledge — pick…

1. Find the missing number in the array Input: [1, 2, 3, 4, 6, 7, 8, 9, 10] Output: 5 const find_missing = function(input) { let n = input.length + 1; let sum = 0; for (let i in input) { sum += input[i]; } return Math.floor((n * (n + 1)) / 2) - sum; }; 2. Inverting integers Input: num…

Tips for writing concise JavaScript code — Preface JavaScript is constantly evolving and upgrading, and more and more new features make our code concise. This article will introduce six new JavaScript features. Let’s study them together. 1. Use “Object.hasOwn” instead of “in” operator Sometimes, we want to know whether a property exists on an object and use the “in” operator or “obj.hasOwnProperty” to do so…

Yup, you’re probably using them incorrectly — I'm tired of seeing the same tutorials pop up every couple of weeks. "JWTokens are the recommended auth method because of scalability." "JWTokens are easier to use." "JWTokens are stateless, so you don't use memory on the server." Let me tell you something. These people probably don't know any better. …

A simple solution to a common problem — How it happens It’s easy to create object literals in JavaScript.

Save hours and avoid headaches by using these resources. — I have been using React for a little over 2 years and once you look past the steep learning curve, it is a solid, well-rounded library. In the last 2 years, I have developed multiple applications of all sorts with a wide range of tools, ranging from relational databases to…

Conquer your interviewer. — Recently, one of my friends was asked this question during an interview. This question actually examines the interviewee’s understanding of performance optimization and is related to a lot of topics. Here I will analyze this question with you. Create a server To facilitate subsequent testing, we can use node to create a simple…

Sometimes, we want to reduce the number of times we fire a function or method call in response to user events in web apps. For example, when a user is typing in a search query, we want him to stop typing for some time before we fire the API request…

Consider the possibility that you are going headless or building an SaaS application and are not relying on a server side programming language to do the work for you, you might sometimes find yourself in need of needing to remove HTML from a string. …

Recently, one of my padawans came to me for help and advice on a school project. After a quick glance at its code, I was immediately stunned by the massive use of the querySelector and querySelectorAll methods to retrieve elements by their id or class only. When I asked him…

Introduction JavaScript decorators are a relatively new feature in JavaScript that allows adding new behavior to existing functions and objects without modifying their underlying code. You can achieve it by using a special syntax that uses an @ symbol before the function name or object key. …

A Step by step guide with an example project — In web applications, all the data you show on the page should reside somewhere, for example, cache, database, storage account, etc. You need to fetch the data from the different sources and do some processing and then render the data on the UI. …

A simpler way to authenticate users with web3 using signed messages It’s no secret that the Ethereum login will soon become a user standard and passwords will no longer be needed. Nevertheless, dApp development is still a fairly young direction and many standards for their development are still set. Now…

Build your own native UIs in JavaScript — In this series, I go through different common-use case scenarios in which your first thought could be using a library or making something completely custom from scratch, even when there are native ways of achieving the same. Check out the full list of articles for this series: You Don’t Need…

Motivation For the past few years, Node became one of the most popular back-end solutions. It’s very easy to bootstrap an app on Node and start handling HTTP requests on the fly. …

The Intersection Observer API is a Web platform API that allows for observing changes to how much of a target element’s area intersects with that of an ancestor element or the viewport. …

Because who doesn’t love to build things with just a single line — What is the thing you do if you want to impress a professional developer? It’s simple: Solve a complex problem with simple logic and as few lines of code as possible. With the introduction of ES6 arrow functions, it is possible to create one-liners that look elegant and simple. In…

Useful HTML features and tips that you should know. — HTML is a mandatory markup language for the web. If you don’t know at least some HTML basics, don’t tell me you’re a web developer. The good thing about HTML is that it has a lot of tags, attributes, and features that we can benefit from. …

My thoughts on clean code — Recently I have finished reading the classic Clean Code by Uncle Bob. As I like to jot down everything I read, I thought it would be a great idea to summarize the book and create a handy playbook. Obviously, this list isn't complete. It will probably evolve and transform in…