fix(useDebouncedState): Add factory function overload to type, clarify setter purity

Author: jquense

src/useDebouncedState.ts

@@ -5,7 +5,9 @@ import useDebouncedCallback, {
 
 /**
  * Similar to `useState`, except the setter function is debounced by
- * the specified delay.
+ * the specified delay. Unlike `useState`, the returned setter is not "pure" having
+ * the side effect of scheduling an update in a timeout, which makes it unsafe to call
+ * inside of the component render phase.
  *
  * ```ts
  * const [value, setValue] = useDebouncedState('test', 500)
@@ -17,10 +19,11 @@ import useDebouncedCallback, {
  * @param delayOrOptions The milliseconds delay before a new value is set, or options object
  */
 export default function useDebouncedState<T>(
-  initialState: T,
+  initialState: T | (() => T),
   delayOrOptions: number | UseDebouncedCallbackOptions,
 ): [T, Dispatch<SetStateAction<T>>] {
   const [state, setState] = useState(initialState)
+
   const debouncedSetState = useDebouncedCallback<Dispatch<SetStateAction<T>>>(
     setState,
     delayOrOptions,