From 54f63e1cf18d57c4a727675f91a49742a9bf1dd0 Mon Sep 17 00:00:00 2001
From: Homa Wong <homawong@gmail.com>
Date: Sat, 29 Oct 2022 18:27:06 -0700
Subject: [PATCH] feat: add `isNothing()`

---
 src/utils/common.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/utils/common.ts b/src/utils/common.ts
index 27a93845..c4df7027 100644
--- a/src/utils/common.ts
+++ b/src/utils/common.ts
@@ -10,7 +10,9 @@ import {
 	ImmerState,
 	hasMap,
 	Archtype,
-	die
+	die,
+	NOTHING,
+	Nothing
 } from "../internal"
 
 /** Returns true if the given value is an Immer draft */
@@ -215,3 +217,7 @@ export function isFrozen(obj: any): boolean {
 	// See #600, IE dies on non-objects in Object.isFrozen
 	return Object.isFrozen(obj)
 }
+
+export function isNothing(value: unknown): value is Nothing {
+	return value === NOTHING
+}