Svelte · Senior · Question 7 of 75

What is the cost of deep `$state` proxies, and how do you control it?

✓Correct answer: Every property access goes through a proxy and nested objects are wrapped lazily; for large immutable data use $state.raw or plain variables
2There is no cost; proxies are free
3Proxies copy the object on each read

Explanation

Only use $state for values that drive effects, deriveds or the template. Non-reactive data can stay in normal variables.

Further reading

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