JavaScript Array Group / / No Comments Managing, sorting, and manipulating data with JavaScript is a skill we’ve often delegated to third party libraries like lodash. As the JavaScript language progresses, however, these features eventually get. added to the JavaScript specification. Two such APIs for grouping of Array data are `Array.prototype.group and Array.prototype.groupToMap. Array.prototype.group To group an array of objects by a given property, call the group method with function that returns the grouping string: const teams = [ { name: "Arsenal", origin: "London", tier: "legendary" }, { name: "Manchester United", origin: "Manchester", tier: "legendary" }, { name: "Liverpool", origin: "Liverpool", tier: "legendary"... more → Posted in: JavaScript Tagged with: Array, Group, JavaScript
How to Control CSS Animations with JavaScript / / No Comments When it comes to animations on the web, developers need to measure the animation’s requirements with the right technology — CSS or JavaScript. Many animations are manageable with CSS but JavaScript will always provide more control. With document.getAnimations, however, you can use JavaScript to manage CSS animations! The document.getAnimations method returns an array of CSSAnimation objects. CSSAnimation provides a host of information about the animation: playState, timeline, effect, and events like onfinish. You can then modify those objects to adjust animations: // Make all CSS animations on the page twice as fast document.getAnimations().forEach((animation) ={ animation.playbackRate... more → Posted in: JavaScript Tagged with: animations, Control, JavaScript
JavaScript print Events / / No Comments Media queries provide a great way to programmatically change behavior depending on viewing state. We can target styles to device, pixel ratio, screen size, and even print. That said, it’s also nice to have JavaScript events that also allow us to change behavior. Did you know you’re provided events both before and after printing? I’ve always used @media print in stylesheets to control print display, but JavaScript provides beforeprint and afterprint events: function toggleImages(hide = false) { document.querySelectorAll('img').forEach(img ={ img.style.display = hide ? 'none' : ''; }); } // Hide images to save toner/ink during printing window.addEventListener('beforeprint',... more → Posted in: JavaScript Tagged with: events, JavaScript, print
Detect Browser Bars Visibility with JavaScript / / No Comments It’s one thing to know about what’s in the browser document, it’s another to have insight as to the user’s browser itself. We’ve gotten past detecting which browser the user is using, and we’re now into knowing what pieces of the browser UI users are seeing. Browsers provide window.personalbar, window.locationbar, and window.menubar properties, with the shape of { visible : /*boolean*/} as its value: if(window.personalbar.visible || window.locationbar.visible || window.menubar.visible) { console.log("Please hide your personal, location, and menubar for maximum screen space"); } What would you use these properties for? Maybe providing a warning to users... more → Posted in: JavaScript Tagged with: Bars, browser, Detect, JavaScript, visibility
Detect XR Support with JavaScript / / No Comments A few years ago I wrote an article about how to detect VR support with JavaScript. Since that time, a whole lot has changed. “Augmented reality” became a thing and terminology has moved to “XR”, instead of VR or AR. As such, the API has needed to evolve. The presence of navigator.xr signals that the browser supports the WebXR API and XR devices: const supportsXR = 'xr' in window.navigator; I really like using in for feature checking rather than if(navigator.xr), as simply invoking that could cause some initialization to take place. In future posts we’ll explore identifying and connecting to different devices. The post Detect XR Support with JavaScript appeared... more → Posted in: JavaScript Tagged with: Detect, JavaScript, Support
Another Update to my Slideshow Web Component – JavaScript Support / / No Comments Last month I shared a simple web component I built to embed slideshows onto web pages. If you didn’t get a chance to read that, you can see it in action in this CodePen below: See the Pen Slideshow Web Component by Raymond Camden (@cfjedimaster) on CodePen. After I wrote this, Šime Vidas shared an excellent update to my component with some great modifications. I talked about this version in a blog post, and it’s the version I’ll be using for my post today. What am I covering today? When I demonstrated how to use my web component, it was done via a script include (well, it’s on CodePen, but you get the idea), and then a bit of HTML. Here’s an example. (And... more → Posted in: JavaScript Tagged with: Another, Component, JavaScript, Slideshow, Support, update
How to Determine a JavaScript Promise’s Status / / No Comments Promises have changed the landscape of JavaScript. Many old APIs have been reincarnated to use Promises (XHR to fetch, Battery API), while new APIs trend toward Promises. Developers can use async/await to handle promises, or then/catch/finally with callbacks, but what Promises don’t tell you is their status. Wouldn’t it be great if the Promise.prototype provided developers a status property to know whether a promise is rejected, resolved, or just done? My research led me to this gist which I found quite clever. I took some time to modify a bit of code and add comments. The following solution provides helper methods for determining a Promise’s status: // Uses setTimeout with... more → Posted in: JavaScript Tagged with: determine, JavaScript, promises, status
Detect System Theme Preference Change Using JavaScript / / No Comments JavaScript and CSS allow users to detect the user theme preference with CSS’ prefers-color-scheme media query. It’s standard these days to use that preference to show the dark or light theme on a given website. But what if the user changes their preference while using your app? To detect a system theme preference change using JavaScript, you need to combine matchMedia, prefers-color-scheme, and an event listener: window.matchMedia('(prefers-color-scheme: dark)') .addEventListener('change',({ matches }) ={ if (matches) { console.log("change to dark mode!") } else { console.log("change to light mode!") } }) The change event of the matchMedia API notifies you... more → Posted in: JavaScript Tagged with: Change, Detect, JavaScript, Preference, system, theme, using