Svelte 5
Can the models correctly write Svelte 5 components? Do they avoid using patterns from earlier versions?
Prompt
Write a counter tool using Svelte 5. It must increment the number when the button is pressed. It must display whether the count value is even or odd. And it must log to the console every time the button is pressed. Return only the Svelte component, fenced in by triple backticks (```).
Answer guidance
This sort of thing (except more likely to be all in one file). ``` // counter.svelte.js export function createCounter(initialCount = 0) { let count = $state(initialCount); let doubled = $derived(count * 2); let isEven = $derived(count % 2 === 0); function increment() { count += 1; } $effect(() => { console.log(`Count changed to ${count}`); }); return { get count() { return count; }, get doubled() { return doubled; }, get isEven() { return isEven; }, increment }; } // App.svelte <script> import { createCounter } from './counter.svelte.js'; const counter = createCounter(5); </script> <button onclick={counter.increment}> Count: {counter.count} (Doubled: {counter.doubled}, {counter.isEven ? 'Even' : 'Odd'}) </button> ```
```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Svelte 5 Counter</title>
<!-- This special script enables Svelte 5 to run in the browser without a build step -->
<script src="https://svelte-5-preview.vercel.app/svelte.js"></script>
<style>
body {
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
display: flex;
justify-content: center;
align-items: center;
height: 100vh;
margin: 0;
background-color: #f0f0f0;
color: #333;
}
#app {
background-color: white;
padding: 2rem 3rem;
border-radius: 12px;
box-shadow: 0 4px 12px rgba(0,0,0,0.1);
text-align: center;
}
h1 {
color: #ff3e00;
font-size: 2.5rem;
margin-bottom: 1rem;
}
p {
font-size: 1.5rem;
margin: 0.5rem 0;
}
.count {
font-weight: bold;
font-size: 3rem;
color: #444;
}
.parity {
font-style: italic;
color: #666;
}
button {
margin-top: 1.5rem;
padding: 1rem 2rem;
font-size: 1.2rem;
font-weight: bold;
color: white;
background-color: #ff3e00;
border: none;
border-radius: 8px;
cursor: pointer;
transition: background-color 0.2s ease, transform 0.1s ease;
}
button:hover {
background-color: #c93100;
}
button:active {
transform: scale(0.98);
}
</style>
</head>
<body>
<!--
The `data-target` attribute tells the Svelte script
which DOM element to render this component into.
-->
<div id="app"></div>
<!--
This is the Svelte 5 component.
The script tag type="text/svelte" is processed by the svelte.js library included above.
-->
<script type="text/svelte" data-target="app">
<script>
// Use $state for reactive values in Svelte 5
let count = $state(0);
// use $derived for values that are calculated from state
const parity = $derived(count % 2 === 0 ? 'Even' : 'Odd');
// This function handles the button click
function increment() {
count += 1;
// Log to the browser console every time the button is pressed
console.log(`Button clicked! New count is: ${count}`);
}
</script>
<h1>Svelte 5 Counter</h1>
<p>Count is: <span class="count">{count}</span></p>
<p class="parity">The number is {parity}</p>
<button onclick={increment}>
Click me!
</button>
</script>
</body>
</html>
```Drag to resize
```svelte
<script>
let count = 0;
function increment() {
count += 1;
console.log('Button pressed. Count:', count);
}
function isEven() {
return count % 2 === 0;
}
</script>
<button on:click={increment}>Increment</button>
<p>Count: {count}</p>
<p>The count is {isEven() ? 'even' : 'odd'}.</p>
```Drag to resize
```
<script>
let count = 0;
function increment() {
count += 1;
console.log(`Button pressed. Current count: ${count}`);
}
$: parity = count % 2 === 0 ? 'Even' : 'Odd';
</script>
<main style="font-family: sans-serif; text-align: center; margin-top: 2em;">
<h1>Counter Tool</h1>
<p style="font-size: 2em;">{count}</p>
<p>The number is <strong>{parity}</strong>.</p>
<button on:click={increment} style="font-size: 1.2em; padding: 0.5em 1.2em;">Increment</button>
</main>
```Drag to resize
```svelte
<script>
let count = 0
function increment() {
count += 1
console.log('Counter updated:', count)
}
</script>
<main>
<button on:click={increment}>
Press me
</button>
<p>Count: {count}</p>
<p>
Status: {count % 2 === 0 ? 'even' : 'odd'}
</p>
</main>
```Drag to resize
```html
<!DOCTYPE html>
<html lang="en">
<head>
<script src="https://cdn.jsdelivr.net/npm/svelte@5.0.0-next.1/internal/index.mjs"></script>
<style>
.counter {
font-family: Arial, sans-serif;
text-align: center;
margin-top: 50px;
}
button {
padding: 10px 20px;
font-size: 16px;
cursor: pointer;
}
</style>
</head>
<body>
<div id="app"></div>
<script>
const { component, createEventDispatcher } = svelte;
function Counter() {
let count = 0;
const increment = () => {
count += 1;
console.log(`Count: ${count}`);
};
const isEven = () => count % 2 === 0;
return `
<div class="counter">
<h1>Count: ${count}</h1>
<p>${isEven() ? 'Even' : 'Odd'}</p>
<button on:click=${increment}>Increment</button>
</div>
`;
}
component(Counter, { target: document.getElementById('app') });
</script>
</body>
</html>
```Drag to resize
```
<script>
let count = 0;
function increment() {
count += 1;
console.log('Button pressed. Count:', count);
}
</script>
<div>
<h1>Counter: {count}</h1>
<p>Count is {count % 2 === 0 ? 'even' : 'odd'}</p>
<button on:click={increment}>Increment</button>
</div>
<style>
div {
font-family: sans-serif;
text-align: center;
margin: 2rem;
}
button {
padding: 0.5rem 1rem;
font-size: 1rem;
cursor: pointer;
}
</style>
```Drag to resize
```svelte
<script>
let count = 0;
function handleClick() {
count += 1;
console.log(`Button pressed. Count is now ${count}`);
}
$: parity = count % 2 === 0 ? 'even' : 'odd';
</script>
<main>
<h1>Count: {count}</h1>
<p>The count is {parity}.</p>
<button on:click={handleClick}>
Increment
</button>
</main>
```Drag to resize
```svelte
<script>
import { count } from './store.js';
function handleClick() {
count.update(n => n + 1);
console.log('Button pressed');
}
$: parity = $count % 2 === 0 ? 'even' : 'odd';
</script>
<button on:click={handleClick}>Increment ({$count})</button>
<p>The count is {$count} and it is {parity}.</p>
```Drag to resize
```html
<script>
let count = $state(0);
function increment() {
count++;
console.log(`Button pressed. Count: ${count}`);
}
$effect(() => {
console.log(`Current count: ${count}`); // Will run on every count change
});
</script>
<div class="counter-container">
<h2>Count: {count}</h2>
<p>Number is {count % 2 === 0 ? 'even' : 'odd'}</p>
<button on:click={increment}>Increment</button>
</div>
<style>
.counter-container {
font-family: Arial, sans-serif;
text-align: center;
max-width: 300px;
margin: 20px auto;
padding: 20px;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0,0,0,0.1);
background-color: #f9f9f9;
}
h2 {
color: #333;
margin-top: 0;
}
p {
color: #666;
font-size: 18px;
margin: 15px 0;
}
button {
background-color: #4CAF50;
color: white;
border: none;
padding: 10px 20px;
font-size: 16px;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.2s;
}
button:hover {
background-color: #45a049;
}
</style>
```Drag to resize
```html
<script>
let count = 0;
function increment() {
count += 1;
console.log(`Button pressed. Current count: ${count}`);
}
$: parity = count % 2 === 0 ? 'even' : 'odd';
</script>
<div>
<h1>Counter: {count}</h1>
<p>The current count is <strong>{parity}</strong></p>
<button on:click={increment}>Increment</button>
</div>
```Drag to resize
```svelte
<script>
let count = 0;
function increment() {
count += 1;
console.log('Count pressed:', count);
}
</script>
<style>
body {
font-family: Arial, sans-serif;
text-align: center;
padding-top: 50px;
}
button {
padding: 10px 20px;
font-size: 16px;
margin-top: 20px;
}
</style>
<main>
<h1>Counter Tool</h1>
<p>Count: {count}</p>
<p>{count % 2 === 0 ? 'Even' : 'Odd'}</p>
<button on:click={increment}>Increment</button>
</main>
```Drag to resize
```svelte
<script>
let count = $state(0);
function increment() {
count++;
console.log(`Button pressed! Count is now: ${count}`);
}
const isEven = $derived(count % 2 === 0);
</script>
<div>
<h1>Counter Tool</h1>
<p>Count: {count}</p>
<p>The count is: {isEven ? 'Even' : 'Odd'}</p>
<button onclick={increment}>Increment</button>
</div>
<style>
div {
text-align: center;
padding: 2rem;
font-family: Arial, sans-serif;
}
button {
padding: 0.5rem 1rem;
font-size: 1rem;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
}
button:hover {
background-color: #0056b3;
}
p {
margin: 1rem 0;
font-size: 1.1rem;
}
</style>
```Drag to resize