From 0c4e3c61e66a7d12990897e7d0b0cd9438efdb88 Mon Sep 17 00:00:00 2001
From: Micah Engle-Eshleman <micah@befunky.com>
Date: Mon, 1 Feb 2021 10:50:27 -0800
Subject: [PATCH] Make ContextDetail.unsubscribe property optional

Fixes Typescript compilation error due to unsubscribe property
not existing on ContextDetail when a context is used without a provider.
---
 src/create-context.ts | 3 ++-
 src/use-context.ts    | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/create-context.ts b/src/create-context.ts
index ed0169f..5a624a1 100644
--- a/src/create-context.ts
+++ b/src/create-context.ts
@@ -20,8 +20,9 @@ interface ContextDetail<T> {
   Context: Context<T>;
   callback: (value: T) => void;
 
+  // These properties will not exist if a context consumer lacks a provider
   value: T;
-  unsubscribe: (this: Context<T>) => void;
+  unsubscribe?: (this: Context<T>) => void;
 }
 
 function makeContext(component: ComponentCreator): Creator {
diff --git a/src/use-context.ts b/src/use-context.ts
index df3bc88..53be227 100644
--- a/src/use-context.ts
+++ b/src/use-context.ts
@@ -55,7 +55,7 @@ const useContext = hook(class<T> extends Hook<[Context<T>], T, Element> {
       composed: true, // to pass ShadowDOM boundaries
     }));
 
-    const { unsubscribe, value } = detail as ContextDetail<T>;
+    const { unsubscribe = null, value } = detail as ContextDetail<T>;
 
     this.value = unsubscribe ? value : Context.defaultValue;