Svelte · Junior · Question 15 of 76

Is an object declared with `$state` deeply reactive?

let todo = $state({ text: "Buy milk", done: false });
todo.done = true;

✓Correct answer: Yes: plain objects and arrays become reactive proxies, so mutating a property updates the UI
2No: you must reassign the whole object
3Only if you call todo.update()

Explanation

Array methods like push also trigger updates. For large data that is only reassigned, $state.raw avoids the proxy overhead.

Further reading

Svelte: $state ↗

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