2 files changed, 6 insertions, 6 deletions
diff --git a/ext/js/display/display-generator.js b/ext/js/display/display-generator.js
index 0b3236e9..0caf4d71 100644
--- a/ext/js/display/display-generator.js
+++ b/ext/js/display/display-generator.js
@@ -17,7 +17,6 @@
  */
 
 import {ExtensionError} from '../core/extension-error.js';
-import {isObject} from '../core/utilities.js';
 import {getDisambiguations, getGroupedPronunciations, getTermFrequency, groupKanjiFrequencies, groupTermFrequencies, groupTermTags, isNonNounVerbOrAdjective} from '../dictionary/dictionary-data-util.js';
 import {HtmlTemplateCollection} from '../dom/html-template-collection.js';
 import {distributeFurigana, getKanaMorae, getPitchCategory, isCodePointKanji} from '../language/ja/japanese.js';
@@ -257,7 +256,7 @@ export class DisplayGenerator {
             if (error instanceof DocumentFragment || error instanceof Node) {
                 div.appendChild(error);
             } else {
-                let message = isObject(error) && typeof error.message === 'string' ? error.message : `${error}`;
+                let message = error.message;
                 let link = null;
                 if (error instanceof ExtensionError && error.data !== null && typeof error.data === 'object') {
                     const {referenceUrl} = /** @type {import('core').UnknownObject} */ (error.data);
diff --git a/ext/js/display/display-history.js b/ext/js/display/display-history.js
index bc4f1539..183368d0 100644
--- a/ext/js/display/display-history.js
+++ b/ext/js/display/display-history.js
@@ -17,7 +17,8 @@
  */
 
 import {EventDispatcher} from '../core/event-dispatcher.js';
-import {generateId, isObject} from '../core/utilities.js';
+import {isObjectNotArray} from '../core/object-utilities.js';
+import {generateId} from '../core/utilities.js';
 
 /**
  * @augments EventDispatcher<import('display-history').Events>
@@ -38,12 +39,12 @@ export class DisplayHistory extends EventDispatcher {
 
         const historyState = history.state;
         const {id, state} = (
-            typeof historyState === 'object' && historyState !== null ?
+            isObjectNotArray(historyState) ?
             historyState :
             {id: null, state: null}
         );
         /** @type {?import('display-history').EntryState} */
-        const stateObject = typeof state === 'object' || state === null ? state : null;
+        const stateObject = isObjectNotArray(state) ? state : null;
         /** @type {import('display-history').Entry} */
         this._current = this._createHistoryEntry(id, location.href, stateObject, null, null);
     }
@@ -189,7 +190,7 @@ export class DisplayHistory extends EventDispatcher {
     _updateStateFromHistory() {
         let state = history.state;
         let id = null;
-        if (isObject(state)) {
+        if (isObjectNotArray(state)) {
             id = state.id;
             if (typeof id === 'string') {
                 const entry = this._historyMap.get(id);