perf: add useMemo to the return value of useTheme

client/src/lib/useTheme.ts

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useState } from "react";
+import { useCallback, useEffect, useMemo, useState } from "react";
 
 type Theme = "light" | "dark" | "system";
 
@@ -36,16 +36,17 @@ const useTheme = (): [Theme, (mode: Theme) => void] => {
     };
   }, [theme]);
   
-  return [
+  const setThemeWithSideEffect = useCallback((newTheme: Theme) => {
-    theme,
-    useCallback((newTheme: Theme) => {
     setTheme(newTheme);
     localStorage.setItem("theme", newTheme);
     if (newTheme !== "system") {
       document.documentElement.classList.toggle("dark", newTheme === "dark");
     }
-    }, []),
+  }, []);
-  ];
+  return useMemo(() => [
+    theme,
+    setThemeWithSideEffect,
+  ], [theme]);
 };
 
 export default useTheme;