In this tutorial we will implement a JavaScript fake API. Often this helps whenever there is no backend yet and you need to implement your frontend against some kind of realistic data. Fake it till you make it! JavaScript Fake API Let's get started. First of all, we need some data which would normally come from our backend's database, but which…

The countBy function is one of the functions why people use Lodash in their JavaScript code base. Here I want to give you a brief example on how to implement countBy in vanilla JavaScript without Lodash by just using JavaScript's reduce method. Let's say we have the following array of objects and we want to count them by property (here color…

The groupBy function is one of the functions why people use Lodash in their JavaScript code base. Here I want to give you a brief example on how to implement groupBy in vanilla JavaScript without Lodash by just using JavaScript's reduce method. Let's say we have the following array of objects and we want to group them by property (here color…

Eventually everyone came across the case that JavaScript's replace function, which is available on a JavaScript string primitive , does only replace one occurrence of the matched term. Here I want to show you briefly how to replace all occurrences in JavaScript with two different ways. The first way uses a regular expression to find all matches…

Functions are first-class citizens in JavaScript. That's why you will early on hear about callback functions in JavaScript, which are a super powerful asset when writing JavaScript code. Here I want to give you a brief introduction to them. Callback functions are usually passed as argument to functions: In this case, our printText function takes…

When you have learned about JavaScript promises for the first time, you learned about the promise's methods then and catch. While the former's callback function is called whenever a JavaScript promise resolves successfully, the latter is used for error handling: Eventually you have learned about async/await in JavaScript as alternative to a…

There are two error handling scenarios in JavaScript. Either an error is thrown from a third-party (e.g. library, database, API) or you want to throw an error yourself. While you have the error at your hands for the former, for the latter you need to new it yourself: Sometimes you want to throw custom errors though. I learned that you can create…

I have always been of the understanding there are no common sense rules about how to create a minimal Node.js application with Babel. In my search for these answers, it seemed that every tutorial I came across showed something different. As a result, I wanted to streamline this project setup for my readers and myself, so I developed a common…

There are three different ways to declare a variable in JavaScript: const, let and var. Historically, var has been the only way of declaring a JavaScript variable : An addition to JavaScript -- to be specific: JavaScript ES6 in 2015 -- has made const and let available to the language: Obviously more options on how to declare and define a…