Basic Svelte
Introduction
Bindings
Advanced Svelte
Advanced reactivity
Motion
Advanced bindings
Advanced transitions
Context API
Special elements
<script module>
Next steps
Basic SvelteKit
Introduction
Routing
Loading data
Headers and cookies
Shared modules
API routes
$app/state
Errors and redirects
Advanced SvelteKit
Page options
Link options
Advanced routing
Advanced loading
Environment variables
Conclusion
While you should generally use CSS for transitions as much as possible, there are some effects that can’t be achieved without JavaScript, such as a typewriter effect:
App
function typewriter(node, { speed = 1 }) {
const valid = node.childNodes.length === 1 && node.childNodes[0].nodeType === Node.TEXT_NODE;
if (!valid) {
throw new Error(`This transition only works on elements with a single text node child`);
}
const text = node.textContent;
const duration = text.length / (speed * 0.01);
return {
duration,
tick: (t) => {
const i = Math.trunc(text.length * t);
node.textContent = text.slice(0, i);
}
};
}previous next
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<script>
let visible = $state(false);
function typewriter(node, { speed = 1 }) {const valid = node.childNodes.length === 1 && node.childNodes[0].nodeType === Node.TEXT_NODE;
if (!valid) {throw new Error(`This transition only works on elements with a single text node child`);
}
return {};}
</script>
<label>
<input type="checkbox" bind:checked={visible} />visible
</label>
{#if visible}<p transition:typewriter>
The quick brown fox jumps over the lazy dog
</p>
{/if}