Fix : Properly clear App Cache and IndexedDB on Resetfix reset btn to clear cache #1136 by infinityanant · Pull Request #1413 · kiwix/kiwix-js

infinityanant · 2026-02-07T18:30:20Z

Problem

The reset function was not properly clearing the app cache and IndexedDB because:

Cache deletion failed silently: The code relied on getCacheNames() which queries the Service Worker. When no Service Worker controller was available, it returned null and skipped cache deletion entirely.
Race condition: The reset function triggered app reload before async cleanup operations (IndexedDB and Cache API deletions) completed, leaving data behind.

Solution

Changed cache deletion to use caches.keys() directly instead of querying the Service Worker, ensuring caches are always accessible
Wrapped IndexedDB and Cache API deletions in Promises
Used Promise.all() to wait for all async cleanup operations to complete before reloading the app
This ensures both kiwixjs-appCache and kiwixjs-assetsCache are properly deleted, along with IndexedDB databases

Testing

Verified that after clicking "Reset App":

Cache storage drops from ~17MB to 0MB
IndexedDB databases (collDB) are deleted
App reloads only after all cleanup completes

Fixes #1136

infinityanant · 2026-03-12T20:58:26Z

Hi @Jaifroid, could you please review this PR whenever you have a moment? I'd be happy to implement any changes or improvements you suggest. Thanks!

Copilot

Pull request overview

This PR fixes the “Reset App” behavior so that CacheStorage and IndexedDB are actually cleared before the app reloads, even when no Service Worker controller is available.

Changes:

Switch cache deletion to use caches.keys() and delete caches directly via the Cache API.
Convert IndexedDB and Cache API deletions into Promises and wait for completion with Promise.all() before reloading.
Minor formatting adjustments in settingsStore.js (function spacing/indentation).

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Copilot · 2026-03-23T13:40:23Z

www/js/lib/settingsStore.js

+            cachePromise = caches.keys().then(function (cacheNames) {
+                if (cacheNames && cacheNames.length > 0) {
+                    var deletePromises = cacheNames.map(function (cacheName) {
+                        console.debug('Deleting cache: ' + cacheName);
+                        return caches.delete(cacheName);
                    });
+                    return Promise.all(deletePromises);


caches.keys() returns all CacheStorage entries for the origin, which can include caches unrelated to this app (if multiple apps share the same domain). Consider filtering cacheNames to only delete Kiwix caches (e.g. by known names from the SW or a kiwix prefix) to avoid wiping other apps' caches on the same origin.

Copilot · 2026-03-23T13:40:23Z

www/js/lib/settingsStore.js

+                indexedDBPromise = indexedDB.databases().then(function (dbs) {
+                    var deletePromises = dbs.map(function (db) {
                        console.debug('Deleting ' + db.name + '...');
+                        return new Promise(function (resolve) {
+                            var req = indexedDB.deleteDatabase(db.name);
+                            req.onsuccess = resolve;


In the indexedDB.databases() branch, db.name can be null/undefined (per IDBDatabaseInfo). Calling indexedDB.deleteDatabase(db.name) will coerce it to a string like 'null'/'undefined'. Please guard/skip entries without a valid name before attempting deletion.

Copilot · 2026-03-23T13:40:24Z

www/js/lib/settingsStore.js

+                        return new Promise(function (resolve) {
+                            var req = indexedDB.deleteDatabase(db.name);
+                            req.onsuccess = resolve;
+                            req.onerror = resolve; // Resolve even on error
+                        });


The IndexedDB delete promise resolves on onsuccess/onerror but does not handle onblocked. If any DB connection is still open, deleteDatabase may fire onblocked and never reach success/error, causing the reset to hang and never reload. Please handle onblocked (and consider logging req.error on onerror) so the overall reset can complete deterministically.

Copilot · 2026-03-23T13:40:24Z

www/js/lib/settingsStore.js

+                        deleteRequest.onerror = function (ev) {
+                            console.error('Error deleting ' + dbName + '...', ev);
+                            resolve(); // Resolve even on error
+                        };


Same as above for the Firefox branch: the deleteDatabase request can become blocked by open connections and never fire onsuccess/onerror, which would prevent Promise.all(...) from resolving and stop the reload. Please attach an onblocked handler (and optionally surface/log blocked state) to ensure reset completes.

Suggested change

};

};

deleteRequest.onblocked = function (ev) {

console.warn('Deletion of ' + dbName + ' is blocked, proceeding with reset...', ev);

resolve(); // Resolve even when blocked to avoid hanging the reset

};

Copilot · 2026-03-23T13:40:24Z

www/js/lib/settingsStore.js

+
+

There are multiple extra blank lines before getCacheNames that were introduced in this change. Please remove the redundant empty lines to keep formatting consistent.

Suggested change

Copilot · 2026-03-23T13:40:25Z

www/js/lib/settingsStore.js

+// function reset(object) {
+//     // 1. Clear any cookie entries
+//     if (!object || object === 'cookie') {
+//         var regexpCookieKeys = /(?:^|;)\s*([^=]+)=([^;]*)/ig;
+//         var currentCookie = document.cookie;
+//         var foundCrumb = false;
+//         var cookieCrumb = regexpCookieKeys.exec(currentCookie);
+//         while (cookieCrumb !== null) {
+//             // DEV: Note that we don't use the keyPrefix in legacy cookie support
+//             foundCrumb = true;
+//             // This expiry date will cause the browser to delete the cookie crumb on next page refresh
+//             document.cookie = cookieCrumb[1] + '=;expires=Thu, 21 Sep 1979 00:00:01 UTC;';
+//             cookieCrumb = regexpCookieKeys.exec(currentCookie);
+//         }
+//         if (foundCrumb) console.debug('All cookie keys were expired...');
+//     }
+
+//     // 2. Clear any localStorage settings
+//     if (!object || object === 'localStorage') {
+//         if (params.storeType === 'local_storage') {
+//             localStorage.clear();
+//             console.debug('All Local Storage settings were deleted...');
+//         }
+//     }
+


The old reset implementation is left in the file as a large commented-out block. This adds noise and makes future maintenance harder; git history already preserves the previous version. Please remove the commented-out function block rather than keeping it inline.

Suggested change

// function reset(object) {

// // 1. Clear any cookie entries

// if (!object || object === 'cookie') {

// var regexpCookieKeys = /(?:^|;)\s*([^=]+)=([^;]*)/ig;

// var currentCookie = document.cookie;

// var foundCrumb = false;

// var cookieCrumb = regexpCookieKeys.exec(currentCookie);

// while (cookieCrumb !== null) {

// // DEV: Note that we don't use the keyPrefix in legacy cookie support

// foundCrumb = true;

// // This expiry date will cause the browser to delete the cookie crumb on next page refresh

// document.cookie = cookieCrumb[1] + '=;expires=Thu, 21 Sep 1979 00:00:01 UTC;';

// cookieCrumb = regexpCookieKeys.exec(currentCookie);

// }

// if (foundCrumb) console.debug('All cookie keys were expired...');

// }

// // 2. Clear any localStorage settings

// if (!object || object === 'localStorage') {

// if (params.storeType === 'local_storage') {

// localStorage.clear();

// console.debug('All Local Storage settings were deleted...');

// }

// }

fix reset btn to clear cache

917b830

Jaifroid self-requested a review February 8, 2026 16:13

Jaifroid assigned infinityanant Feb 8, 2026

Jaifroid added user interface accessibility labels Feb 8, 2026

Jaifroid added this to the v4.4 milestone Feb 8, 2026

infinityanant added 2 commits March 7, 2026 01:52

Merge branch 'main' into fix-reset-btn

aee9e29

Merge branch 'main' into fix-reset-btn

ea07aeb

Jaifroid requested a review from Copilot March 23, 2026 13:36

Copilot started reviewing on behalf of Jaifroid March 23, 2026 13:37 View session

Copilot AI reviewed Mar 23, 2026

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Fix : Properly clear App Cache and IndexedDB on Resetfix reset btn to clear cache #1136#1413

Fix : Properly clear App Cache and IndexedDB on Resetfix reset btn to clear cache #1136#1413
infinityanant wants to merge 3 commits intokiwix:mainfrom
infinityanant:fix-reset-btn

infinityanant commented Feb 7, 2026

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infinityanant commented Mar 12, 2026 •

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-                        };
+                        };
+                        deleteRequest.onblocked = function (ev) {
+                            console.warn('Deletion of ' + dbName + ' is blocked, proceeding with reset...', ev);
+                            resolve(); // Resolve even when blocked to avoid hanging the reset
+                        };

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infinityanant commented Feb 7, 2026

Problem

Solution

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infinityanant commented Mar 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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infinityanant commented Mar 12, 2026 •

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