# Bug report SWRMutationConfiguration.optimisticData types is not correct ## Description / Observed Behavior What kind of issues did you encounter with SWR? the optimisticData Fn has a second injected parameter ## Expected Behavior How did you expect SWR to behave here? its types should be same as useSWR's MutatorOptions ## Repro Steps / Code Example just log it , b is not undefined `optimisticData: (a, b, c) => { console.log("fnData", a.preferences, b.preferences, c); ... });` ## Additional Context SWR version. the latest <img width="1247" height="502" alt="Image" src="https://github.com/user-attachments/assets/116b3eb2-07aa-4762-8ed2-a75b77d5d9a3" /> <img width="1959" height="250" alt="Image" src="https://github.com/user-attachments/assets/e8e3d622-63fd-4d38-9030-004f75ef7ac3" />