Svelte · Senior · Question 8 of 75

What does `createSubscriber` from `svelte/reactivity` solve?

✓Correct answer: Integrating external event sources (like matchMedia or a WebSocket) so they subscribe only while something reactive reads them
2Subscribing to SvelteKit routes
3Creating stores from runes

Explanation

It's how MediaQuery is built: the listener is attached when the value is read in an effect and removed when no effects depend on it.

Further reading

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