How to use matchMedia to create a performant custom viewport hook
How to use matchMedia to create a performant custom viewport hook
By Dave Bitter
3 min read
Unfortunately, sometimes you need to write viewport-based logic in your JavaScript code. Usually, this is done with a listener on the window for a resize. Let’s look at a better way.
- Authors
- Name
- Dave Bitter
- linkedinDave Bitter
- twitter@dave_bitter
- Github
- githubDaveBitter
- Website
- websiteBlog
What’s wrong with listening for the resize event?
Nothing really, it does the job. This has been the way for years now. There is a downside that comes with this solution, though. Let’s say you have four breakpoints:
smwith a maximum width of 767 pixelsmdwith a minimum width of 768 pixelslgwith a minimum width of 1024 pixelsxlwith a minimum width of 1200 pixels
You’re only really interested in these four pixel values. However, when listening to the resize event, you’ll get an update for every pixel value in between as well. Let's say you are implementing a utility for your React.js project to offer this. A custom React.js hook you can write will probably look a bit like this:
import { useEffect, useState } from 'react'
type ViewportBreakpoint = 'sm' | 'md' | 'lg' | 'xl'
const useViewportBreakpoint = () => {
const [viewportBreakpoint, setViewportBreakpoint] = useState<ViewportBreakpoint>('sm')
useEffect(() => {
const onResize = () => {
if (window.innerWidth < 768) {
setViewportBreakpoint('sm')
return
}
if (window.innerWidth < 1024) {
setViewportBreakpoint('md')
return
}
if (window.innerWidth < 1200) {
setViewportBreakpoint('lg')
return
}
setViewportBreakpoint('xl')
}
window.addEventListener('resize', onResize)
onResize()
return () => window.removeEventListener('resize', onResize)
}, [])
return viewportBreakpoint
}
export default useViewportBreakpoint
Sure, you could use requestAnimationFrame to optimize this a bit further, but inherently you’re going to receive far more updates than you actually need.
Cool, so how does matchMedia fix that?
On the window object, you’ll find a method called matchMedia. With this method, you can listen for a media query, just like in CSS, to respond to. The basic usage looks like this:
const mql = window.matchMedia('(min-width: 768px)')
const handleQueryChange = ({ matches }) => {
console.log(matches) // true or false
}
mql.addEventListener('change', handleQueryChange)
That’s it! Every time the viewport passed 768 pixels, you’ll receive an update. You can then handle your business logic based on whether the media query is met.
Let’s make a custom hook!
Now, let’s take the above principle and create a custom hook that will support all four of the viewport breakpoints:
import { useEffect, useState } from 'react'
type ViewportBreakpoint = 'sm' | 'md' | 'lg' | 'xl'
const useViewportBreakpoint = () => {
const [viewportBreakpoint, setViewportBreakpoint] = useState<ViewportBreakpoint>('sm')
useEffect(() => {
const smQuery = window.matchMedia('(max-width: 767px)')
const mdQuery = window.matchMedia('(min-width: 768px) and (max-width: 1023px)')
const lgQuery = window.matchMedia('(min-width: 1024px) and (max-width: 1199px)')
const xlQuery = window.matchMedia('(min-width: 1200px)')
const handleSmQueryChange = ({ matches }: { matches: boolean }) =>
matches && setViewportBreakpoint('sm')
const handleMdQueryChange = ({ matches }: { matches: boolean }) =>
matches && setViewportBreakpoint('md')
const handleLgQueryChange = ({ matches }: { matches: boolean }) =>
matches && setViewportBreakpoint('lg')
const handleXlQueryChange = ({ matches }: { matches: boolean }) =>
matches && setViewportBreakpoint('xl')
smQuery.addEventListener('change', handleSmQueryChange)
mdQuery.addEventListener('change', handleMdQueryChange)
lgQuery.addEventListener('change', handleLgQueryChange)
xlQuery.addEventListener('change', handleXlQueryChange)
handleSmQueryChange({ matches: smQuery.matches })
handleMdQueryChange({ matches: mdQuery.matches })
handleLgQueryChange({ matches: lgQuery.matches })
handleXlQueryChange({ matches: xlQuery.matches })
return () => {
smQuery.removeEventListener('change', handleSmQueryChange)
mdQuery.removeEventListener('change', handleMdQueryChange)
lgQuery.removeEventListener('change', handleLgQueryChange)
xlQuery.removeEventListener('change', handleXlQueryChange)
}
}, [])
return viewportBreakpoint
}
export default useViewportBreakpoint
Wow! Quite a bit of boilerplate. As you can only listen for on media query, you’ll have to quadruple the code. Before we optimize this, let’s have a look at the different parts.
Firstly, you now have to set a minimum and maximum width for the different media queries. Previously, you could bail out as soon as a viewport was matched. As these are all different events, they will all trigger. This can cause multiple media queries to match. By adding maximum widths, you can circumvent this.
Secondly, the callback function when a change event is detected does receive the media query it matched against, but we then have to map which ViewportBreakpoint it belongs to. If you don’t want to add this complexity, you have to create four separate callbacks.
Finally, as you have to add four event listeners, you have to remove four of them as well. This is a bit annoying.
Time to refactor
Firstly, you could refactor the callback to a single one and check each media query to conditionally set the value for the active viewport breakpoint:
import { useEffect, useState } from 'react'
type ViewportBreakpoint = 'sm' | 'md' | 'lg' | 'xl'
const useViewportBreakpoint = () => {
const [viewportBreakpoint, setViewportBreakpoint] = useState<ViewportBreakpoint>('sm')
useEffect(() => {
const smQuery = window.matchMedia('(max-width: 767px)')
const mdQuery = window.matchMedia('(min-width: 768px) and (max-width: 1023px)')
const lgQuery = window.matchMedia('(min-width: 1024px) and (max-width: 1199px)')
const xlQuery = window.matchMedia('(min-width: 1200px)')
const checkMatch = () => {
smQuery.matches && setViewportBreakpoint('sm')
mdQuery.matches && setViewportBreakpoint('md')
lgQuery.matches && setViewportBreakpoint('lg')
xlQuery.matches && setViewportBreakpoint('xl')
}
smQuery.addEventListener('change', checkMatch)
mdQuery.addEventListener('change', checkMatch)
lgQuery.addEventListener('change', checkMatch)
xlQuery.addEventListener('change', checkMatch)
checkMatch()
return () => {
smQuery.removeEventListener('change', checkMatch)
mdQuery.removeEventListener('change', checkMatch)
lgQuery.removeEventListener('change', checkMatch)
xlQuery.removeEventListener('change', checkMatch)
}
}, [])
return viewportBreakpoint
}
export default useViewportBreakpoint
This works because you added the maximum widths. Only one will ever match and update the state of the viewport breakpoint.
This does still feel a bit repetitive, though. How can you make this more DRY? Let’s create an array with multiple viewport breakpoints and their media query. You can then loop over this array and execute the logic:
import { useEffect, useState } from 'react'
type ViewportBreakpoint = 'sm' | 'md' | 'lg' | 'xl'
type ViewportBreakpointConfig = {
size: ViewportBreakpoint
mql: MediaQueryList
}
const useViewportBreakpoint = () => {
const [viewportBreakpoint, setViewportBreakpoint] = useState<ViewportBreakpoint>('sm')
useEffect(() => {
const mqls: ViewportBreakpointConfig[] = [
{ size: 'sm', mql: window.matchMedia('(max-width: 767px)') },
{ size: 'md', mql: window.matchMedia('(min-width: 768px) and (max-width: 1023px)') },
{ size: 'lg', mql: window.matchMedia('(min-width: 1024px) and (max-width: 1199px)') },
{ size: 'xl', mql: window.matchMedia('(min-width: 1200px)') },
]
const checkMatch = () =>
mqls.forEach(({ size, mql }) => mql.matches && setViewportBreakpoint(size))
mqls.forEach(({ mql }) => mql.addEventListener('change', checkMatch))
checkMatch()
return () => {
mqls.forEach(({ mql }) => mql.removeEventListener('change', checkMatch))
}
}, [])
return viewportBreakpoint
}
export default useViewportBreakpoint
There you have it! You can now use this custom hook in your React.js application to execute viewport-based logic.
Final thoughts
Once in a while, you get surprised about a better way of doing something you’ve been doing the same for years. So, is this a new technique? Well, quite the opposite! The support for matchMedia is great:
The next time you have to create a similar utility, try matchMedia out!
Upcoming events
The Test Automation Meetup
PLEASE RSVP SO THAT WE KNOW HOW MUCH FOOD WE WILL NEED Test automation is a cornerstone of effective software development. It's about creating robust, predictable test suites that enhance quality and reliability. By diving into automation, you're architecting systems that ensure consistency and catch issues early. This expertise not only improves the development process but also broadens your skillset, making you a more versatile team member. Whether you're a developer looking to enhance your testing skills or a QA professional aiming to dive deeper into automation, RSVP for an evening of learning, delicious food, and the fusion of coding and quality assurance! 🚀🚀 18:00 – 🚪 Doors open to the public 18:15 – 🍕 Let’s eat 19:00 – 📢 First round of Talks 19:45 – 🍹 Small break 20:00 – 📢 Second round of Talks 20:45 – 🍻 Drinks 21:00 – 🙋♀️ See you next time? First Round of Talks: The Power of Cross-browser Component Testing - Clarke Verdel, SR. Front-end Developer at iO How can you use Component Testing to ensure consistency cross-browser? Second Round of Talks: Omg who wrote this **** code!? - Erwin Heitzman, SR. Test Automation Engineer at Rabobank How can tests help you and your team? Beyond the Unit Test - Christian Würthner, SR. Android Developer at iO How can you do advanced automated testing for, for instance, biometrics? RSVP now to secure your spot, and let's explore the fascinating world of test automation together!
| Coven of Wisdom - Amsterdam
Go to page for The Test Automation MeetupCoven of Wisdom - Herentals - Winter `24 edition
Worstelen jij en je team met automated testing en performance? Kom naar onze meetup waar ervaren sprekers hun inzichten en ervaringen delen over het bouwen van robuuste en efficiënte applicaties. Schrijf je in voor een avond vol kennis, heerlijk eten en een mix van creativiteit en technologie! 🚀 18:00 – 🚪 Deuren open 18:15 – 🍕 Food & drinks 19:00 – 📢 Talk 1 20:00 – 🍹 Kleine pauze 20:15 – 📢 Talk 2 21:00 – 🙋♀️ Drinks 22:00 – 🍻 Tot de volgende keer? Tijdens deze meetup gaan we dieper in op automated testing en performance. Onze sprekers delen heel wat praktische inzichten en ervaringen. Ze vertellen je hoe je effectieve geautomatiseerde tests kunt schrijven en onderhouden, en hoe je de prestaties van je applicatie kunt optimaliseren. Houd onze updates in de gaten voor meer informatie over de sprekers en hun specifieke onderwerpen. Over iO Wij zijn iO: een groeiend team van experts die end-to-end-diensten aanbieden voor communicatie en digitale transformatie. We denken groot en werken lokaal. Aan strategie, creatie, content, marketing en technologie. In nauwe samenwerking met onze klanten om hun merken te versterken, hun digitale systemen te verbeteren en hun toekomstbestendige groei veilig te stellen. We helpen klanten niet alleen hun zakelijke doelen te bereiken. Samen verkennen en benutten we de eindeloze mogelijkheden die markten in constante verandering bieden. De springplank voor die visie is talent. Onze campus is onze broedplaats voor innovatie, die een omgeving creëert die talent de ruimte en stimulans geeft die het nodig heeft om te ontkiemen, te ontwikkelen en te floreren. Want werken aan de infinite opportunities van morgen, dat doen we vandaag.
| Coven of Wisdom Herentals
Go to page for Coven of Wisdom - Herentals - Winter `24 editionMastering Event-Driven Design
PLEASE RSVP SO THAT WE KNOW HOW MUCH FOOD WE WILL NEED Are you and your team struggling with event-driven microservices? Join us for a meetup with Mehmet Akif Tütüncü, a senior software engineer, who has given multiple great talks so far and Allard Buijze founder of CTO and founder of AxonIQ, who built the fundaments of the Axon Framework. RSVP for an evening of learning, delicious food, and the fusion of creativity and tech! 🚀 18:00 – 🚪 Doors open to the public 18:15 – 🍕 Let’s eat 19:00 – 📢 Getting Your Axe On Event Sourcing with Axon Framework 20:00 – 🍹 Small break 20:15 – 📢 Event-Driven Microservices - Beyond the Fairy Tale 21:00 – 🙋♀️ drinks 22:00 – 🍻 See you next time? Details: Getting Your Axe On - Event Sourcing with Axon Framework In this presentation, we will explore the basics of event-driven architecture using Axon Framework. We'll start by explaining key concepts such as Event Sourcing and Command Query Responsibility Segregation (CQRS), and how they can improve the scalability and maintainability of modern applications. You will learn what Axon Framework is, how it simplifies implementing these patterns, and see hands-on examples of setting up a project with Axon Framework and Spring Boot. Whether you are new to these concepts or looking to understand them more, this session will provide practical insights and tools to help you build resilient and efficient applications. Event-Driven Microservices - Beyond the Fairy Tale Our applications need to be faster, better, bigger, smarter, and more enjoyable to meet our demanding end-users needs. In recent years, the way we build, run, and operate our software has changed significantly. We use scalable platforms to deploy and manage our applications. Instead of big monolithic deployment applications, we now deploy small, functionally consistent components as microservices. Problem. Solved. Right? Unfortunately, for most of us, microservices, and especially their event-driven variants, do not deliver on the beautiful, fairy-tale-like promises that surround them.In this session, Allard will share a different take on microservices. We will see that not much has changed in how we build software, which is why so many “microservices projects” fail nowadays. What lessons can we learn from concepts like DDD, CQRS, and Event Sourcing to help manage the complexity of our systems? He will also show how message-driven communication allows us to focus on finding the boundaries of functionally cohesive components, which we can evolve into microservices should the need arise.
| Coven of Wisdom - Utrecht
Go to page for Mastering Event-Driven Design