Rob Gravelle

In business applications, dashboards provide at-a-glance views of Key Performance Indicators (KPIs) relevant to a particular objective or process. As business services have moved to the Cloud, so too have dashboards. Web-based dashboards can draw their data from a number of sources, from databases, feeds, other sites, and can refresh parts of the page at […]

Floating point rounding is a task which all developers have to perform at some point. There are actually several types of rounding algorithms, including: round-up round-down round-toward-nearest arithmetic rounding round-half-up round-half-down round-half-even round-half-odd round-toward-zero round-away-from-zero round-ceiling round-floor truncation (chopping) round-alternate round-random (stochastic rounding) to name but a few. Of these, you are probably most familiar […]

For newbies, Angular’s component-based architecture takes a bit of getting used to. Unlike the Object-oriented (OOP) design of programming languages like Java, Angular is not able to enforce encapsulation with quite the same voracity, mainly due to JavaScript’s unrestricted access to the DOM. But, as they say, just because you CAN do something, doesn’t mean […]

One of the advantages to using Angular Material controls is that they come with accessibility baked in. As such, they include role and aria-* attributes, as well as support for standard keyboard navigation. Should you decide to build your own widgets, you will also have to consider accessibility, or else risk losing some users. Case […]

The twin mouseenter and mouseleave Element events are the standard way to bind JavaScript code to hover events. But what happens if we need to detect hovered elements within another event handler? I myself had to answer this very question when I implemented focus handling for dozens of SVG elements. Part of the focus treatment […]

Directives are classes that add additional behavior to elements in your Angular applications. Angular directives can help manage many aspects of the DOM, including forms, lists, styles, and many more. Angular includes several built-in directives, and you can define your own to attach custom behavior to elements in the DOM. In this tutorial, we’ll learn […]

In Angular applications, the NgClass directive is the de facto way to set CSS classes dynamically on DOM elements. We learned all about its many permutations in the Assigning Dynamic Classes with NgClass article. Today, we’ll be exploring a specific use of NgClass to toggle an element’s visibility on and off according to user interactions. Specifically, we’ll be using […]

Even if you pay attention to cleaning up your subscriptions when components are destroyed, there is still the potential for memory leaks from nested RxJS subscriptions. In fact, there are other problems with nested subscriptions as well, such as timing issues. For these reasons, nested subscriptions have earned the top spot in the list of […]

I couldn’t count the number of tables that I’ve worked on that required at least one sortable column. It’s the kind of thing that users love, perhaps because it gives them tremendous control over their data. In the early days of the Web, I used JavaScript to implement custom sorting. Now, there are many third-party […]

One of the most challenging tasks for Date and time libraries is the parsing of International Dates and Times. They come in such a wide array of formats that it’s all but impossible to accommodate all of them. Different Date libraries approach this problem using a variety of solutions, some better than others. The Moment.js […]

We’ve all seen HTML Selects and Options with custom text and wondered how the developer achieved it. Common upgrades include the inclusion of icons, checkboxes, and additional information that is not part of the Select options. For example, here’s one that lets the user select toppings for their pizza and displays the first ingredient selected, […]

Moment.js is still widely regarded as the king of the JavaScript date libraries, despite being designated a legacy project by its maintainers in 2020. Now, the search is on for a worthy successor. Though it might be a little early to declare a winner, by all accounts, it is looking like Luxon is the front-runner. Not only […]