Svelte 5: Array<{ name: string }>, array.reverse() causes $inspect to run array.length times

[PuruVJ]

Describe the bug

If an array of objects(files) is declared with $state is reversed, $inspect(files) should give only one log, but it logs arra.length number of times(if 4 items in array, 4 update logs). Does that mean that all the individual objects are also being updated? If so, that's breaking fine-grained reactivity.

ASIDE: Is it supposed to log Proxy object to the console? I assumed it would unwrap it all and give the nice and original object array. Not a breaker for me, just a opinion.

Reproduction

https://svelte-5-preview.vercel.app/#H4sIAAAAAAAAE3VRwWrCQBD9lWErGEESW0oPqQql9Ki92JP2EOPEbEmyYWdikWX_vbOJCC32tDPvvXm8nXGq0BWSSrdONVmNKlUvbaumis9taOiEFaP0ZDqbB2ROudUtL3fNjpMEPtav76vV23oDXCJUGTE8gGasCdgAIfZ409V7tGAK6NpDxiI0R7o4iOxooLCmhsfQPAW8QoY-GSxgRCwj0TbgO3YQcqYwlpzxEG8MfvqHjLE53YAzmfmif4jB7Bcv8a6SUgtlmtvkd3nm0sQ5XYc_J8_ySDHSDbWYc9T_ZzKAhLzRNZqOo2gCiyW4wbPXxBZPaAmjIGY_hfvZbCb1PLnsHoKJu8MsLy9byqgvfBhwoYpDMA_zvU3kVC4JWi93rM1BFxoPKmXbof_0P_qv3QwCAgAA

Logs

No response

System Info

svelte 5 repl

Severity

annoyance

[trueadm]

This is to be expected. When you do reverse(), under-the-hood, the method is mutating every entry in the array. So it's always going to be O(n) updates. This operation is going to be O(n) and thus should result in the same amount of updates.

[Rich-Harris]

That's true, but it's still unexpected and a bit unhelpful. Since it's really something that's specific to arrays, I wonder if we could special-case mutating array methods (which only needs to happen in DEV, since $inspect only works in DEV) such that only the final state is reported? It's pretty annoying if you get 101 updates when you shift() an array with 100 items

[trueadm]

@Rich-Harris How the old $log worked was that it only recorded the last set to something, rather than capture them all. Maybe we could do the same here, but instead – the first set.