From 8c0c616f1523d5e93ab5c408c5be1c4ebb6884bd Mon Sep 17 00:00:00 2001
From: Madeorsk <madeorsk@protonmail.com>
Date: Sat, 13 Jul 2024 16:37:24 +0200
Subject: [PATCH] Add usePreviousValue hook.

---
 src/Utils.tsx | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/Utils.tsx b/src/Utils.tsx
index 53412de..6147e56 100644
--- a/src/Utils.tsx
+++ b/src/Utils.tsx
@@ -1,3 +1,4 @@
+import {useEffect, useRef} from "react";
 
 export type Modify<T, R> = Omit<T, keyof R> & R;
 
@@ -31,3 +32,21 @@ export function normalizeString(str: string): string
 			.replace?.(/[\u0300-\u036f]/g, "")
 		: "";
 }
+
+/**
+ * Get the previous value of a given value.
+ * @param currentValue The current value.
+ */
+export function usePreviousValue<T>(currentValue: T): T
+{
+	// Get the reference to the previous value.
+	const ref = useRef<T>();
+
+	// If the value has changed, saving it in the reference after rendering.
+	useEffect(() => {
+		ref.current = currentValue;
+	}, [currentValue]);
+
+	// Get the previous value.
+	return ref?.current ?? undefined;
+}