diff --git a/packages/lib/src/Tools.ts b/packages/lib/src/Tools.ts
index bb14fa5..2cd4d84 100644
--- a/packages/lib/src/Tools.ts
+++ b/packages/lib/src/Tools.ts
@@ -77,14 +77,14 @@ export const mapKeys = <T extends Record<string, any>>(f: (v: string) => string,
   return r as T
 }
 
-export const mapVals = <T extends Record<string, any>>(f: (v: any) => any, x: T) => {
-  const r: Record<string, any> = {}
+export const mapVals = <V, U>(f: (v: V) => U, x: Record<string, V>) => {
+  const r: Record<string, U> = {}
 
   for (const [k, v] of Object.entries(x)) {
     r[k] = f(v)
   }
 
-  return r as T
+  return r
 }
 
 export const mergeLeft = <T extends Record<string, any>>(a: T, b: T) => ({...b, ...a})
diff --git a/packages/util/package.json b/packages/util/package.json
index 99ac1d5..0d0bcb5 100644
--- a/packages/util/package.json
+++ b/packages/util/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@welshman/util",
-  "version": "0.0.32",
+  "version": "0.0.33",
   "author": "hodlbod",
   "license": "MIT",
   "description": "A collection of nostr-related utilities.",
diff --git a/packages/util/src/Filters.ts b/packages/util/src/Filters.ts
index ef68004..bd6cd43 100644
--- a/packages/util/src/Filters.ts
+++ b/packages/util/src/Filters.ts
@@ -214,7 +214,7 @@ export const getFilterResultCardinality = (filter: Filter) => {
   return null
 }
 
-export const trimFilter = (filter: Filter) =>
-  mapVals(v => Array.isArray(v) && v.length > 1000 ? shuffle(v).slice(0, 1000) : v, filter)
+export const trimFilter = (filter: Filter): Filter =>
+  mapVals(v => Array.isArray(v) && v.length > 1000 ? shuffle(v as string[]).slice(0, 1000) : v, filter) as Filter
 
 export const trimFilters = (filters: Filter[]) => filters.map(trimFilter)