Coveralls is used to show you the test coverage of your JavaScript application. Let's see how it can be used for your JavaScript project which is already on GitHub and connected to your Travis CI due to the previous CI setup tutorial. First, sign up at Coveralls.io with your GitHub account. Second, synchronize your GitHub repositories and toggle…
The following tutorial will show you how to set up continuous integration with Travis CI. The continuous integration should make sure that the JavaScript application is built and tested with every change in the code base that reaches your CI. For instance, the CI would fail if the tests are not running through successfully or if the build process…
Eventually you will come across the concept of a JavaScript Closure. I want to give you a step by step walkthrough on how to implement a JavaScript Closure. Along the way, you will find out yourself why it makes sense to implement certain things with JavaScript Closures. The whole source code can be found on GitHub . If you want to code along the…
After all my teachings about React, be it online for a larger audience or on-site for companies transitioning to web development and React, I always come to the conclusion that React is all about JavaScript. Newcomers to React but also myself see it as an advantage , because you carry your JavaScript knowledge for a longer time around compared to…
I started out with JavaScript -- and web development in general -- when everything felt brittle. Developing entire applications with jQuery felt just wrong, the JavaScript APIs (e.g. DOM API) weren't mature enough, the lack of supportive CSS made aligning HTML without hacks impossible, and in general, there was no tooling to ship qualitative web…
This tutorial teaches you how to build your first Web Components and how to use them in your applications. Before we get started, let's take a moment to learn more about Web Components in general: In recent years, Web Components, also called Custom Elements , have become a standard API for several browsers which allow developers to implement…
You may be already using npm (node package manager) for installing libraries (node packages) to your JavaScript projects. For instance, in Node.js you may be used to Express.js for creating REST APIs . In frontend development, you may be used to React.js to build component-based web applications. This makes you a consumer of the npm ecosystem…
The concept of a Reducer became popular in JavaScript with the rise of Redux as state management solution for React . But no worries, you don't need to learn Redux to understand Reducers. Basically reducers are there to manage state in an application. For instance, if a user writes something in an HTML input field, the application has to manage…
The Map Function is one of the many Methods existing on the JavaScript Array prototype . If you want to do a deep dive on prototypical inheritance, here's a great read by Kyle Simpson on how prototypes work under the hood . For this article it will be sufficient to know that the methods on the Array prototype are available to every array that…
First off, this tutorial assumes that you have some knowledge of how React works. If you're just getting started to React, I'd highly recommend reading through The Road to learn React before trying to dive into ReasonReact. It's really important to have at least a basic foundational understanding of React. After all, ReasonReact is an abstraction…
