From 48bf17614f95b2388e4c72fd9225da0e970bce7d Mon Sep 17 00:00:00 2001
From: Felix Roos <flix91@gmail.com>
Date: Thu, 18 Aug 2022 00:26:57 +0200
Subject: [PATCH] fix: runtime error reify undefined

---
 packages/core/pattern.mjs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/core/pattern.mjs b/packages/core/pattern.mjs
index 48e52643..db1df876 100644
--- a/packages/core/pattern.mjs
+++ b/packages/core/pattern.mjs
@@ -1222,7 +1222,7 @@ export function pure(value) {
 
 export function isPattern(thing) {
   // thing?.constructor?.name !== 'Pattern' // <- this will fail when code is mangled
-  const is = thing instanceof Pattern || thing._Pattern;
+  const is = thing instanceof Pattern || thing?._Pattern;
   if (!thing instanceof Pattern) {
     console.warn(
       `Found Pattern that fails "instanceof Pattern" check.