Optimizing Frontend Performance with Lazy Loading Techniques
Introduction
And it was painful—not just for me, but for everyone who visited my site. Watching the performance waterfall chart on Chrome DevTools was like witnessing a crime scene. Red bars. Long tasks.
That’s when I heard about lazy loading.
Not the kind where your code lies on the couch and does nothing (I already had too much of that). I’m talking about the art of only loading things when they’re actually needed.
And it changed everything.
Let me walk you through my (hilariously frustrating but ultimately rewarding) journey into the world of lazy loading—and why you should consider doing it too.
What Is Lazy Loading Anyway?
Okay, imagine you go to a buffet. You’re hungry, but instead of handing you one plate of food, the staff dumps the entire buffet table onto your plate… including the desserts you’re not eating until an hour later.
That’s what a lot of websites do by default: they load everything, all at once, whether or not it’s immediately useful.
Lazy loading, on the other hand, says:
“Hey, let’s only fetch and render what the user actually needs right now. And we’ll bring in the rest… later.”
This applies to:
- images
- videos
- scripts
- components
If it doesn’t need to be loaded up front, it can chill in the background.
How I Discovered My App Was a Sluggish Beast
I built a dashboard-heavy Vue app.
Gorgeous, animated charts. Massive tables. Lazy GIFs of sloths (ironic, in hindsight).
Users loved the design… if they were patient enough to wait for it to load.
Initial bundle size: 3.8 MB.
That might not sound like much, but on 3G (hello, rural users!), it’s an eternity.
- Mobile bounce rate?
- Analytics? Looked like a ghost town
The First Lazy Load: Images
Before:
html
<img src="huge-banner.jpg" alt="Banner of joy" />
<img loading="lazy" src="huge-banner.jpg" alt="Banner of joy" />
I used Vue Router and realized I didn’t need to load every page component on the initial visit.
const SettingsPage = () => import('./views/SettingsPage.vue');