From 16f023fc666ad674d3dba89206230acbbf974735 Mon Sep 17 00:00:00 2001
From: Tyler Swavely <tyler.r909@gmail.com>
Date: Fri, 23 Aug 2019 00:02:35 -0700
Subject: [PATCH 1/2] fix(useSetState): memoize setState callback

---
 src/useSetState.ts | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/useSetState.ts b/src/useSetState.ts
index d09004390e..ba40da2139 100644
--- a/src/useSetState.ts
+++ b/src/useSetState.ts
@@ -1,12 +1,15 @@
-import { useState } from 'react';
+import { useState, useCallback } from 'react';
 
 const useSetState = <T extends object>(
   initialState: T = {} as T
 ): [T, (patch: Partial<T> | ((prevState: T) => Partial<T>)) => void] => {
   const [state, set] = useState<T>(initialState);
-  const setState = patch => {
-    set(prevState => Object.assign({}, prevState, patch instanceof Function ? patch(prevState) : patch));
-  };
+  const setState = useCallback(
+    patch => {
+      set(prevState => Object.assign({}, prevState, patch instanceof Function ? patch(prevState) : patch));
+    },
+    [set]
+  );
 
   return [state, setState];
 };

From c60ee96be1205281c9684d1ee3ec7ec122fdbccf Mon Sep 17 00:00:00 2001
From: Tyler Swavely <tyler.swavely@nike.com>
Date: Fri, 23 Aug 2019 10:35:05 -0700
Subject: [PATCH 2/2] chore(useSetState): check useSetState for memoized
 callback

---
 src/__tests__/useSetState.test.ts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/__tests__/useSetState.test.ts b/src/__tests__/useSetState.test.ts
index 684ba30bee..4f3b1e39bb 100644
--- a/src/__tests__/useSetState.test.ts
+++ b/src/__tests__/useSetState.test.ts
@@ -40,3 +40,21 @@ it('should merge changes into current state when providing function', () => {
 
   expect(result.current[0]).toEqual({ foo: 'bar', count: 2, someBool: true });
 });
+
+/**
+ * Enforces cases where a hook can safely depend on the callback without
+ * causing an endless rerender cycle: useEffect(() => setState({ data }), [setState]);
+ */
+it('should return a memoized setState callback', () => {
+  const { result, rerender } = setUp({ ok: false });
+  const [, setState1] = result.current;
+
+  act(() => {
+    setState1({ ok: true });
+  });
+  rerender();
+
+  const [, setState2] = result.current;
+
+  expect(setState1).toBe(setState2);
+});