data: CacheableObject: check default update value more gracefully

Fixes a test failure introduced in cebd7f4a, and more generally,
crashes to do with flags: {update: true} but no update: {...}
configuration.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/data/cacheable-object.js b/src/data/cacheable-object.js
index 4a89b774..71dc5bde 100644
--- a/src/data/cacheable-object.js
+++ b/src/data/cacheable-object.js
@@ -132,7 +132,11 @@ export default class CacheableObject {
         return;
       }
 
-      if ('default' in update) {
+      if (
+        typeof update === 'object' &&
+        update !== null &&
+        'default' in update
+      ) {
         this[property] = update?.default;
       } else {
         this[property] = null;