Add some type utils, findFeed, and fix feed listener to use limit: 0 instead of since

packages/lib/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@welshman/lib",
-  "version": "0.4.5",
+  "version": "0.4.6",
   "author": "hodlbod",
   "license": "MIT",
   "description": "A collection of utilities.",

packages/lib/src/Tools.ts

@@ -14,6 +14,14 @@ export const isNotNil = <T>(x: T, ...args: unknown[]) => x !== undefined && x !=
 
 export const assertNotNil = <T>(x: T, ...args: unknown[]) => x!
 
+// ----------------------------------------------------------------------------
+// Working with types
+// ----------------------------------------------------------------------------
+
+export type Override<T, R> = Omit<T, keyof R> & R
+
+export type MakeOptional<T, K extends keyof T> = Override<T, Partial<Pick<T, K>>>
+
 // ----------------------------------------------------------------------------
 // Basic functional programming utilities
 // ----------------------------------------------------------------------------