Articles Tagged JavaScript

Date is weird in JavaScript. It gets on our nerves so much that we reach for libraries (like Date-fns and Moment) the moment (ha!) we need to work with date and time.

But we don't always need to use libraries. Date can actually be quite simple if you know what to watch out for. In this article, I'll walk you through everything you need to know about the Date object.… Read article

Sorting is a super handy JavaScript method that can display the values of an array in a certain order. Whether that’s real estate listings by price, burger joints by distance, or best nearby happy hours by rating, sorting arrays of information is a common need.

If you’re already doing this with JavaScript on a project, you are will likely using the built-in array .sort method, which is in the same family of array methods that includes .filter, .map and … Read article

JavaScript (or ECMAScript) is the programming language that powers the web. Created in May 1995 by Brendan Eich, it’s found its place as a widely-used and versatile technology. Despite its success, it’s been met with its fair share of criticism, especially for idiosyncrasies. Things like objects being casted to string form when used as indices, 1 == "1" returning true, or the notoriously confusing this keyword. A particularly interesting quirk though, is the existence of various techniques for variable privacy.… Read article

Events are used to respond when a user clicks somewhere, focuses on a link with their keyboard, and changes the text in a form. When I first started learning JavaScript, I wrote complicated event listeners. More recently, I've learned how to reduce both the amount of code I write and the number of listeners I need.

Let’s start with a simple example: a few draggable boxes. We want to show the user which colored box they dragged.… Read article

You might not know this, but JavaScript has stealthily accumulated quite a number of observers in recent times, and Intersection Observer is a part of that arsenal. Observers are objects that spot something in real-time — like birdwatchers going to their favorite place to sit and wait for the birds to come.

Different observers observe different things (not everyone watches hawks).

The very first observer I came to know was the Mutation Observer that looks for changes to the DOM … Read article

Some months ago I was on Hacker News (as one does) and I ran across a (now deleted) article about not using if statements. If you’re new to this idea (like I was), you’re in a for a real treat. Just search for "if statements" on Hacker News. You'll get articles proposing that you might not need them, articles that refer to them as a code smell and even the quintessential "considered harmful." Listen, you know a programming … Read article

I wanted to implement a notification message in one of my projects, similar to what you’d see in Google Docs while a document is saving. In other words, a message shows up indicating that the document is saving every time a change is made. Then, once the changes are saved, the message becomes: “All changes saved in Drive.”

Let’s take a look at how we might do that using a boolean value, but actually covering three possible states. This definitely … Read article

On March 6, 2018, a new bug was added to the official Mozilla Firefox browser bug tracker. A developer had noticed an issue with Mozilla's nightly build. The report noted that a 14-day weather forecast widget typically featured on a German website had all of a sudden broken and disappeared. Nothing on the site had changed, so the problem had to be with Firefox.

The problem, the developer noted in his … Read article