javascript / beginner
Snippet
Reactive Declarations
Reactive declarations automatically re-calculate their value whenever any of the variables they reference change. The $: syntax marks a statement as reactive.
snippet.js
javascript
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<script>let count = 0;$: doubled = count * 2;</script><button on:click={() => count++}>{count} doubled is {doubled}</button>
svelte
Breakdown
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let count = 0;
Initializes a standard reactive variable.
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$: doubled = count * 2;
The $: label tells Svelte to re-run this line whenever 'count' changes.