Lazy Loading Components
Defer non-critical component rendering with dynamic imports and intersection observers.
Lazy Loading Components is a free Sveltejs Academy lesson on CoddyKit. This is lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Sveltejs Academy learning path, and your progress syncs across the web and the CoddyKit app. The Sveltejs Academy course includes 4 lessons in total.
Why Lazy Load
Defer loading of heavy or non-critical components to reduce initial bundle size.
Dynamic Import
Use import() to load a module asynchronously.
let Component;
onMount(async () => {
Component = (await import("./Heavy.svelte")).default;
});Render When Loaded
Use <svelte:component> to render the dynamic component.
{#if Component}
<svelte:component this={Component} />
{/if}Intersection Observer
Combine with IntersectionObserver to load when the placeholder enters the viewport.
Action Wrapper
Build a reusable use:lazy action to encapsulate the pattern.
Loading State
Show a skeleton or spinner until the component arrives.
Below-the-Fold Use
Comments, related posts, footer widgets all qualify for lazy loading.
Performance Gains
Reduces initial JS, speeds up TTI, especially on mobile.
Prefetching
Optionally preload modules on hover or near-viewport for snappier interactions.
Avoid Over-Splitting
For tiny components, the overhead of dynamic import outweighs the savings.
Combine With Streaming
For server-rendered pages, streaming + lazy hydration creates fast initial paints.
Quick Check
How do you render a dynamically imported component?
Recap
Lazy-load heavy components with dynamic import + svelte:component, optionally triggered by intersection.
Learn HTML with an AI tutor — free
Write and run real code in your browser, get instant help from a 24/7 AI tutor, and pick up where you left off on the web or in the app.
- Courses
- 41
- Lessons
- 163
Frequently Asked Questions
Is the “Lazy Loading Components” lesson free?
Yes — the full text of “Lazy Loading Components” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Sveltejs Academy course, upgrade to CoddyKit PRO. The Sveltejs Academy course includes 4 lessons in total.
What will I learn in “Lazy Loading Components”?
Defer non-critical component rendering with dynamic imports and intersection observers. You practise Sveltejs Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Sveltejs Academy?
No prior experience is required. Sveltejs Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 4.
How long does the “Lazy Loading Components” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Sveltejs Academy lesson?
Yes. Every Sveltejs Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Code Splitting and Dynamic Imports
- Optimizing Images with @sveltejs/enhanced-img
- Lazy Loading Components
- Profiling SvelteKit Apps