From e554e27095fb2a543ba7085e5481e098502d20af Mon Sep 17 00:00:00 2001
From: Janne Savolainen <janne.savolainen@live.fi>
Date: Mon, 7 Feb 2022 07:39:17 +0200
Subject: [PATCH] Fix observation of asyncComputed when invalidated before ever
 observed

---
 .../injectable-react/src/asyncComputed/asyncComputed.js   | 3 ++-
 .../src/asyncComputed/asyncComputed.test.js               | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/injectable-react/src/asyncComputed/asyncComputed.js b/packages/injectable-react/src/asyncComputed/asyncComputed.js
index d1105434..0ead6e25 100644
--- a/packages/injectable-react/src/asyncComputed/asyncComputed.js
+++ b/packages/injectable-react/src/asyncComputed/asyncComputed.js
@@ -1,3 +1,4 @@
+import { noop } from 'lodash/fp';
 import { computed, createAtom, observable, runInAction, untracked } from 'mobx';
 
 const neutralizeObsoletePromiseSymbol = Symbol.for(
@@ -9,7 +10,7 @@ export default (getObservedPromise, pendingValue) => {
 
   const pendingBox = observable.box(false);
 
-  let neutralizeObsoletePromise;
+  let neutralizeObsoletePromise = noop;
 
   const syncValueBox = observable.box(pendingValue, {
     name: 'sync-value-box-for-async-computed',
diff --git a/packages/injectable-react/src/asyncComputed/asyncComputed.test.js b/packages/injectable-react/src/asyncComputed/asyncComputed.test.js
index b6f9f9e4..ec53cbb4 100644
--- a/packages/injectable-react/src/asyncComputed/asyncComputed.test.js
+++ b/packages/injectable-react/src/asyncComputed/asyncComputed.test.js
@@ -20,6 +20,14 @@ describe('asyncComputed', () => {
       }, 'some-pending-value');
     });
 
+    it('given invalidated before observation, when observed, does not throw', () => {
+      someAsyncComputed.invalidate();
+
+      expect(() => {
+        observe(someAsyncComputed.value, () => {});
+      }).not.toThrow();
+    });
+
     describe('when only status is observed but not value', () => {
       beforeEach(() => {
         observe(someAsyncComputed.pending, () => {});