Wrap usage of setTimeout in helper for background + auxiliary pages

This commit centralizes usage of setTimeout()/clearTimeout() in the
source code at one single location.

platform/common/vapi-common.js

@@ -35,6 +35,116 @@ vAPI.T0 = Date.now();
 
 vAPI.setTimeout = vAPI.setTimeout || self.setTimeout.bind(self);
 
+vAPI.defer = {
+    create(callback) {
+        return new this.Client(callback);
+    },
+    once(delay, ...args) {
+        const delayInMs = vAPI.defer.normalizeDelay(delay);
+        return new Promise(resolve => {
+            vAPI.setTimeout(
+                (...args) => { resolve(...args); },
+                delayInMs,
+                ...args
+            );
+        });
+    },
+    Client: class {
+        constructor(callback) {
+            this.timer = null;
+            this.type = 0;
+            this.callback = callback;
+        }
+        on(delay, ...args) {
+            if ( this.timer !== null ) { return; }
+            const delayInMs = vAPI.defer.normalizeDelay(delay);
+            this.type = 0;
+            this.timer = vAPI.setTimeout(( ) => {
+                this.timer = null;
+                this.callback(...args);
+            }, delayInMs || 1);
+        }
+        offon(delay, ...args) {
+            this.off();
+            this.on(delay, ...args);
+        }
+        onvsync(delay, ...args) {
+            if ( this.timer !== null ) { return; }
+            const delayInMs = vAPI.defer.normalizeDelay(delay);
+            if ( delayInMs !== 0 ) {
+                this.type = 0;
+                this.timer = vAPI.setTimeout(( ) => {
+                    this.timer = null;
+                    this.onraf(...args);
+                }, delayInMs);
+            } else {
+                this.onraf(...args);
+            }
+        }
+        onidle(delay, ...args) {
+            if ( this.timer !== null ) { return; }
+            const delayInMs = vAPI.defer.normalizeDelay(delay);
+            if ( delayInMs !== 0 ) {
+                this.type = 0;
+                this.timer = vAPI.setTimeout(( ) => {
+                    this.timer = null;
+                    this.onric(...args);
+                }, delayInMs);
+            } else {
+                this.onric(...args);
+            }
+        }
+        off() {
+            if ( this.timer === null ) { return; }
+            switch ( this.type ) {
+            case 0:
+                self.clearTimeout(this.timer);
+                break;
+            case 1:
+                self.cancelAnimationFrame(this.timer);
+                break;
+            case 2:
+                self.cancelIdleCallback(this.timer);
+                break;
+            default:
+                break;
+            }
+            this.timer = null;
+        }
+        onraf(...args) {
+            if ( this.timer !== null ) { return; }
+            this.type = 1;
+            this.timer = requestAnimationFrame(( ) => {
+                this.timer = null;
+                this.callback(...args);
+            });
+        }
+        onric(...args) {
+            if ( this.timer !== null ) { return; }
+            this.type = 2;
+            this.timer = self.requestIdleCallback(deadline => {
+                this.timer = null;
+                this.callback(deadline, ...args);
+            });
+        }
+        ongoing() {
+            return this.timer !== null;
+        }
+    },
+    normalizeDelay(delay = 0) {
+        if ( typeof delay === 'object' ) {
+            if ( delay.sec !== undefined ) {
+                return delay.sec * 1000;
+            } else if ( delay.min !== undefined ) {
+                return delay.min * 60000;
+            } else if ( delay.hr !== undefined ) {
+                return delay.hr * 3600000;
+            }
+        }
+        return delay;
+    }
+};
+
 /******************************************************************************/
 
 vAPI.webextFlavor = {

src/js/1p-filters.js

@@ -56,12 +56,17 @@ let cachedUserFilters = '';
 
 /******************************************************************************/
 
-// Add auto-complete ability to the editor.
+// Add auto-complete ability to the editor. Polling is used as the suggested
+// hints also depend on the tabs currently opened.
 
 {
     let hintUpdateToken = 0;
 
-    const responseHandler = function(response) {
+    const getHints = async function() {
+        const response = await vAPI.messaging.send('dashboard', {
+            what: 'getAutoCompleteDetails',
+            hintUpdateToken
+        });
         if ( response instanceof Object === false ) { return; }
         if ( response.hintUpdateToken !== undefined ) {
             const mode = cmEditor.getMode();
@@ -73,15 +78,12 @@ let cachedUserFilters = '';
             }
             hintUpdateToken = response.hintUpdateToken;
         }
-        vAPI.setTimeout(getHints, 2503);
+        timer.on(2503);
     };
 
-    const getHints = function() {
+    const timer = vAPI.defer.create(( ) => {
-        vAPI.messaging.send('dashboard', {
+        getHints();
-            what: 'getAutoCompleteDetails',
+    });
-            hintUpdateToken
-        }).then(responseHandler);
-    };
 
     getHints();
 }
@@ -306,8 +308,7 @@ dom.on('#userFiltersRevert', 'click', revertChanges);
     // https://github.com/gorhill/uBlock/issues/3706
     //   Save/restore cursor position
     {
-        const line =
+        const line = await vAPI.localStorage.getItemAsync('myFiltersCursorPosition');
-            await vAPI.localStorage.getItemAsync('myFiltersCursorPosition');
         if ( typeof line === 'number' ) {
             cmEditor.setCursor(line, 0);
         }
@@ -317,15 +318,14 @@ dom.on('#userFiltersRevert', 'click', revertChanges);
     //   Save/restore cursor position
     {
         let curline = 0;
-        let timer;
         cmEditor.on('cursorActivity', ( ) => {
-            if ( timer !== undefined ) { return; }
+            if ( timer.ongoing() ) { return; }
             if ( cmEditor.getCursor().line === curline ) { return; }
-            timer = vAPI.setTimeout(( ) => {
+            timer.on(701);
-                timer = undefined;
+        });
-                curline = cmEditor.getCursor().line;
+        const timer = vAPI.defer.create(( ) => {
-                vAPI.localStorage.setItem('myFiltersCursorPosition', curline);
+            curline = cmEditor.getCursor().line;
-            }, 701);
+            vAPI.localStorage.setItem('myFiltersCursorPosition', curline);
         });
     }
 

src/js/advanced-settings.js

@@ -118,19 +118,16 @@ const arrayFromString = function(s) {
 /******************************************************************************/
 
 const advancedSettingsChanged = (( ) => {
-    let timer;
-
     const handler = ( ) => {
-        timer = undefined;
+        const changed = hashFromAdvancedSettings(cmEditor.getValue()) !== beforeHash;
-        const changed =
-            hashFromAdvancedSettings(cmEditor.getValue()) !== beforeHash;
         qs$('#advancedSettingsApply').disabled = !changed;
         CodeMirror.commands.save = changed ? applyChanges : function(){};
     };
 
+    const timer = vAPI.defer.create(handler);
+
     return function() {
-        if ( timer !== undefined ) { clearTimeout(timer); }
+        timer.offon(200);
-        timer = vAPI.setTimeout(handler, 100);
     };
 })();
 

src/js/assets.js

@@ -73,20 +73,16 @@ assets.fetch = function(url, options = {}) {
     return new Promise((resolve, reject) => {
     // Start of executor
 
-    const timeoutAfter = µb.hiddenSettings.assetFetchTimeout * 1000 || 30000;
+    const timeoutAfter = µb.hiddenSettings.assetFetchTimeout || 30;
     const xhr = new XMLHttpRequest();
     let contentLoaded = 0;
-    let timeoutTimer;
 
     const cleanup = function() {
         xhr.removeEventListener('load', onLoadEvent);
         xhr.removeEventListener('error', onErrorEvent);
         xhr.removeEventListener('abort', onErrorEvent);
         xhr.removeEventListener('progress', onProgressEvent);
-        if ( timeoutTimer !== undefined ) {
+        timeoutTimer.off();
-            clearTimeout(timeoutTimer);
-            timeoutTimer = undefined;
-        }
     };
 
     const fail = function(details, msg) {
@@ -130,12 +126,11 @@ assets.fetch = function(url, options = {}) {
     const onProgressEvent = function(ev) {
         if ( ev.loaded === contentLoaded ) { return; }
         contentLoaded = ev.loaded;
-        if ( timeoutTimer !== undefined ) {
+        timeoutTimer.offon({ sec: timeoutAfter });
-            clearTimeout(timeoutTimer); 
-        }
-        timeoutTimer = vAPI.setTimeout(onTimeout, timeoutAfter);
     };
 
+    const timeoutTimer = vAPI.defer.create(onTimeout);
+
     // Be ready for thrown exceptions:
     // I am pretty sure it used to work, but now using a URL such as
     // `file:///` on Chromium 40 results in an exception being thrown.
@@ -147,7 +142,7 @@ assets.fetch = function(url, options = {}) {
         xhr.addEventListener('progress', onProgressEvent);
         xhr.responseType = options.responseType || 'text';
         xhr.send();
-        timeoutTimer = vAPI.setTimeout(onTimeout, timeoutAfter);
+        timeoutTimer.on({ sec: timeoutAfter });
     } catch (e) {
         onErrorEvent.call(xhr);
     }
@@ -422,17 +417,14 @@ const unregisterAssetSource = function(assetKey) {
 };
 
 const saveAssetSourceRegistry = (( ) => {
-    let timer;
+    const save = ( ) => {
-    const save = function() {
+        timer.off();
-        timer = undefined;
         cacheStorage.set({ assetSourceRegistry });
     };
+    const timer = vAPI.defer.create(save);
     return function(lazily) {
-        if ( timer !== undefined ) {
-            clearTimeout(timer);
-        }
         if ( lazily ) {
-            timer = vAPI.setTimeout(save, 500);
+            timer.offon(500);
         } else {
             save();
         }
@@ -533,15 +525,14 @@ const getAssetCacheRegistry = function() {
 };
 
 const saveAssetCacheRegistry = (( ) => {
-    let timer;
     const save = function() {
-        timer = undefined;
+        timer.off();
         cacheStorage.set({ assetCacheRegistry });
     };
+    const timer = vAPI.defer.create(save);
     return function(lazily) {
-        if ( timer !== undefined ) { clearTimeout(timer); }
         if ( lazily ) {
-            timer = vAPI.setTimeout(save, 30000);
+            timer.offon({ sec: 30 });
         } else {
             save();
         }
@@ -961,7 +952,6 @@ const updaterUpdated = [];
 const updaterFetched = new Set();
 
 let updaterStatus;
-let updaterTimer;
 let updaterAssetDelay = updaterAssetDelayDefault;
 let updaterAuto = false;
 
@@ -1043,9 +1033,11 @@ const updateNext = async function() {
         fireNotification('asset-update-failed', { assetKey: result.assetKey });
     }
 
-    vAPI.setTimeout(updateNext, updaterAssetDelay);
+    updaterTimer.on(updaterAssetDelay);
 };
 
+const updaterTimer = vAPI.defer.create(updateNext);
+
 const updateDone = function() {
     const assetKeys = updaterUpdated.slice(0);
     updaterFetched.clear();
@@ -1064,8 +1056,7 @@ assets.updateStart = function(details) {
     updaterAuto = details.auto === true;
     if ( updaterStatus !== undefined ) {
         if ( newUpdateDelay < oldUpdateDelay ) {
-            clearTimeout(updaterTimer);
+            updaterTimer.offon(updaterAssetDelay);
-            updaterTimer = vAPI.setTimeout(updateNext, updaterAssetDelay);
         }
         return;
     }
@@ -1073,10 +1064,7 @@ assets.updateStart = function(details) {
 };
 
 assets.updateStop = function() {
-    if ( updaterTimer ) {
+    updaterTimer.off();
-        clearTimeout(updaterTimer);
-        updaterTimer = undefined;
-    }
     if ( updaterStatus !== undefined ) {
         updateDone();
     }

src/js/background.js

@@ -172,7 +172,6 @@ const µBlock = {  // jshint ignore:line
         allowedRequestCount: 0,
     },
     localSettingsLastModified: 0,
-    localSettingsLastSaved: 0,
 
     // Read-only
     systemSettings: {

src/js/benchmarks.js

@@ -69,18 +69,13 @@ import {
 
 const loadBenchmarkDataset = (( ) => {
     let datasetPromise;
-    let ttlTimer;
+
+    const ttlTimer = vAPI.defer.create(( ) => {
+        datasetPromise = undefined;
+    });
 
     return function() {
-        if ( ttlTimer !== undefined ) {
+        ttlTimer.offon({ min: 5 });
-            clearTimeout(ttlTimer);
-            ttlTimer = undefined;
-        }
-
-        setTimeout(( ) => {
-            ttlTimer = undefined;
-            datasetPromise = undefined;
-        }, 5 * 60 * 1000);
 
         if ( datasetPromise !== undefined ) {
             return datasetPromise;

src/js/cachestorage.js

@@ -101,36 +101,27 @@ const cacheStorage = {
 const selectIDB = async function() {
     let db;
     let dbPromise;
-    let dbTimer;
 
     const noopfn = function () {
     };
 
     const disconnect = function() {
-        if ( dbTimer !== undefined ) {
+        dbTimer.off();
-            clearTimeout(dbTimer);
-            dbTimer = undefined;
-        }
         if ( db instanceof IDBDatabase ) {
             db.close();
             db = undefined;
         }
     };
 
+    const dbTimer = vAPI.defer.create(( ) => {
+        disconnect();
+    });
+
     const keepAlive = function() {
-        if ( dbTimer !== undefined ) {
+        dbTimer.offon(Math.max(
-            clearTimeout(dbTimer);
+            µb.hiddenSettings.autoUpdateAssetFetchPeriod * 2 * 1000,
-        }
+            180000
-        dbTimer = vAPI.setTimeout(
+        ));
-            ( ) => {
-                dbTimer = undefined;
-                disconnect();
-            },
-            Math.max(
-                µb.hiddenSettings.autoUpdateAssetFetchPeriod * 2 * 1000,
-                180000
-            )
-        );
     };
 
     // https://github.com/gorhill/uBlock/issues/3156
@@ -192,13 +183,13 @@ const selectIDB = async function() {
                 resolve(null);
                 resolve = undefined;
             };
-            setTimeout(( ) => {
+            vAPI.defer.once(5000).then(( ) => {
                 if ( resolve === undefined ) { return; }
                 db = null;
                 dbPromise = undefined;
                 resolve(null);
                 resolve = undefined;
-            }, 5000);
+            });
         });
         return dbPromise;
     };

src/js/code-viewer.js

@@ -211,7 +211,7 @@ async function setURL(resourceURL) {
     dom.attr(a, 'title', afterURL);
     addPastURLs(afterURL);
     // For unknown reasons, calling focus() synchronously does not work...
-    vAPI.setTimeout(( ) => { cmEditor.focus(); }, 1);
+    vAPI.defer.once(1).then(( ) => { cmEditor.focus(); });
 }
 
 /******************************************************************************/

src/js/codemirror/search.js

@@ -86,16 +86,7 @@ import { i18n$ } from '../i18n.js';
             return;
         }
         if ( queryTextFromSearchWidget(cm) === state.queryText ) { return; }
-        if ( state.queryTimer !== null ) {
+        state.queryTimer.offon(350);
-            clearTimeout(state.queryTimer);
-        }
-        state.queryTimer = setTimeout(
-            () => {
-                state.queryTimer = null;
-                findCommit(cm, 0);
-            },
-            350
-        );
     };
 
     const searchWidgetClickHandler = function(cm, ev) {
@@ -141,7 +132,6 @@ import { i18n$ } from '../i18n.js';
             this.panel = cm.addPanel(this.widget);
         }
         this.queryText = '';
-        this.queryTimer = null;
         this.dirty = true;
         this.lines = [];
         cm.on('changes', (cm, changes) => {
@@ -155,6 +145,9 @@ import { i18n$ } from '../i18n.js';
         cm.on('cursorActivity', cm => {
             updateCount(cm);
         });
+        this.queryTimer = vAPI.defer.create(( ) => {
+            findCommit(cm, 0);
+        });
     };
 
     // We want the search widget to behave as if the focus was on the
@@ -426,10 +419,7 @@ import { i18n$ } from '../i18n.js';
 
     const findCommit = function(cm, dir) {
         const state = getSearchState(cm);
-        if ( state.queryTimer !== null ) {
+        state.queryTimer.off();
-            clearTimeout(state.queryTimer);
-            state.queryTimer = null;
-        }
         const queryText = queryTextFromSearchWidget(cm);
         if ( queryText === state.queryText ) { return; }
         state.queryText = queryText;

src/js/commands.js

@@ -111,19 +111,15 @@ const relaxBlockingMode = (( ) => {
         if ( noReload ) { return; }
 
         // Reload: use a timer to coalesce bursts of reload commands.
-        let timer = reloadTimers.get(tab.id);
+        const timer = reloadTimers.get(tab.id) || (( ) => {
-        if ( timer !== undefined ) {
+            const t = vAPI.defer.create(tabId => {
-            clearTimeout(timer);
-        }
-        timer = vAPI.setTimeout(
-            tabId => {
                 reloadTimers.delete(tabId);
                 vAPI.tabs.reload(tabId);
-            },
+            });
-            547,
+            reloadTimers.set(tab.id, t);
-            tab.id
+            return t;
-        );
+        })();
-        reloadTimers.set(tab.id, timer);
+        timer.offon(547, tab.id);
     };
 })();
 

src/js/cosmetic-filtering.js

@@ -225,10 +225,12 @@ const FilterContainer = function() {
     this.reSimpleHighGeneric = /^(?:[a-z]*\[[^\]]+\]|\S+)$/;
 
     this.selectorCache = new Map();
-    this.selectorCachePruneDelay = 10 * 60 * 1000; // 10 minutes
+    this.selectorCachePruneDelay = 10; // 10 minutes
     this.selectorCacheCountMin = 40;
     this.selectorCacheCountMax = 50;
-    this.selectorCacheTimer = null;
+    this.selectorCacheTimer = vAPI.defer.create(( ) => {
+        this.pruneSelectorCacheAsync();
+    });
 
     // specific filters
     this.specificFilters = new StaticExtFilteringHostnameDB(2);
@@ -274,10 +276,7 @@ FilterContainer.prototype.reset = function() {
     this.duplicateBuster = new Set();
 
     this.selectorCache.clear();
-    if ( this.selectorCacheTimer !== null ) {
+    this.selectorCacheTimer.off();
-        clearTimeout(this.selectorCacheTimer);
-        this.selectorCacheTimer = null;
-    }
 
     // hostname, entity-based filters
     this.specificFilters.clear();
@@ -604,18 +603,6 @@ FilterContainer.prototype.fromSelfie = function(selfie) {
 
 /******************************************************************************/
 
-FilterContainer.prototype.triggerSelectorCachePruner = function() {
-    // Of interest: http://fitzgeraldnick.com/weblog/40/
-    // http://googlecode.blogspot.ca/2009/07/gmail-for-mobile-html5-series-using.html
-    if ( this.selectorCacheTimer !== null ) { return; }
-    this.selectorCacheTimer = vAPI.setTimeout(
-        ( ) => { this.pruneSelectorCacheAsync(); },
-        this.selectorCachePruneDelay
-    );
-};
-
-/******************************************************************************/
-
 FilterContainer.prototype.addToSelectorCache = function(details) {
     const hostname = details.hostname;
     if ( typeof hostname !== 'string' || hostname === '' ) { return; }
@@ -626,7 +613,7 @@ FilterContainer.prototype.addToSelectorCache = function(details) {
         entry = SelectorCacheEntry.factory();
         this.selectorCache.set(hostname, entry);
         if ( this.selectorCache.size > this.selectorCacheCountMax ) {
-            this.triggerSelectorCachePruner();
+            this.selectorCacheTimer.on({ min: this.selectorCachePruneDelay });
         }
     }
     entry.add(details);
@@ -658,7 +645,6 @@ FilterContainer.prototype.removeFromSelectorCache = function(
 /******************************************************************************/
 
 FilterContainer.prototype.pruneSelectorCacheAsync = function() {
-    this.selectorCacheTimer = null;
     if ( this.selectorCache.size <= this.selectorCacheCountMax ) { return; }
     const cache = this.selectorCache;
     const hostnames = Array.from(cache.keys())

src/js/dashboard-common.js

@@ -113,18 +113,18 @@ self.uBlockDashboard.dateNowToSensibleString = function() {
 /******************************************************************************/
 
 self.uBlockDashboard.patchCodeMirrorEditor = (function() {
-    let grabFocusTimer;
     let grabFocusTarget;
 
     const grabFocus = function() {
         grabFocusTarget.focus();
-        grabFocusTimer = grabFocusTarget = undefined;
+        grabFocusTarget = undefined;
     };
+
+    const grabFocusTimer = vAPI.defer.create(grabFocus);
+
     const grabFocusAsync = function(cm) {
         grabFocusTarget = cm;
-        if ( grabFocusTimer === undefined ) {
+        grabFocusTimer.on(1);
-            grabFocusTimer = vAPI.setTimeout(grabFocus, 1);
-        }
     };
 
     // https://github.com/gorhill/uBlock/issues/3646

src/js/dashboard.js

@@ -104,19 +104,19 @@ if ( self.location.hash.slice(1) === 'no-dashboard.html' ) {
 (async ( ) => {
     // Wait for uBO's main process to be ready
     await new Promise(resolve => {
-        const check = ( ) => {
+        const check = async ( ) => {
-            vAPI.messaging.send('dashboard', {
+            try {
-                what: 'readyToFilter'
+                const response = await vAPI.messaging.send('dashboard', {
-            }).then(response => {
+                    what: 'readyToFilter'
+                });
                 if ( response ) { return resolve(true); }
                 const iframe = qs$('#iframe');
                 if ( iframe.src !== '' ) {
                     iframe.src = '';
                 }
-                vAPI.setTimeout(check, 250);
+            } catch(ex) {
-            }).catch(( ) => {
+            }
-                vAPI.setTimeout(check, 250);
+            vAPI.defer.once(250).then(( ) => check());
-            });
         };
         check();
     });

src/js/logger-ui-inspector.js

@@ -336,39 +336,35 @@ const startDialog = (function() {
     let textarea;
     let hideSelectors = [];
     let unhideSelectors = [];
-    let inputTimer;
 
-    const onInputChanged = (function() {
+    const parse = function() {
-        const parse = function() {
+        hideSelectors = [];
-            inputTimer = undefined;
+        unhideSelectors = [];
-            hideSelectors = [];
-            unhideSelectors = [];
 
-            const re = /^([^#]*)(#@?#)(.+)$/;
+        const re = /^([^#]*)(#@?#)(.+)$/;
-            for ( let line of textarea.value.split(/\s*\n\s*/) ) {
+        for ( let line of textarea.value.split(/\s*\n\s*/) ) {
-                line = line.trim();
+            line = line.trim();
-                if ( line === '' || line.charAt(0) === '!' ) { continue; }
+            if ( line === '' || line.charAt(0) === '!' ) { continue; }
-                const matches = re.exec(line);
+            const matches = re.exec(line);
-                if ( matches === null || matches.length !== 4 ) { continue; }
+            if ( matches === null || matches.length !== 4 ) { continue; }
-                if ( inspectedHostname.lastIndexOf(matches[1]) === -1 ) {
+            if ( inspectedHostname.lastIndexOf(matches[1]) === -1 ) {
-                    continue;
+                continue;
-                }
-                if ( matches[2] === '##' ) {
-                    hideSelectors.push(matches[3]);
-                } else {
-                    unhideSelectors.push(matches[3]);
-                }
             }
-
+            if ( matches[2] === '##' ) {
-            showCommitted();
+                hideSelectors.push(matches[3]);
-        };
+            } else {
-
+                unhideSelectors.push(matches[3]);
-        return function parseAsync() {
-            if ( inputTimer === undefined ) {
-                inputTimer = vAPI.setTimeout(parse, 743);
             }
-        };
+        }
-    })();
+
+        showCommitted();
+    };
+
+    const inputTimer = vAPI.defer.create(parse);
+
+    const onInputChanged = ( ) => {
+        inputTimer.on(743);
+    };
 
     const onClicked = function(ev) {
         var target = ev.target;
@@ -433,10 +429,7 @@ const startDialog = (function() {
     };
 
     const stop = function() {
-        if ( inputTimer !== undefined ) {
+        inputTimer.off();
-            clearTimeout(inputTimer);
-            inputTimer = undefined;
-        }
         showInteractive();
         textarea.removeEventListener('input', onInputChanged);
         dialog.removeEventListener('click', onClicked, true);
@@ -513,11 +506,9 @@ const onClicked = function(ev) {
 /******************************************************************************/
 
 const onMouseOver = (function() {
-    var mouseoverTarget = null;
+    let mouseoverTarget = null;
-    var mouseoverTimer = null;
 
-    var timerHandler = function() {
+    const timerHandler = ( ) => {
-        mouseoverTimer = null;
         vAPI.MessagingConnection.sendTo(inspectorConnectionId, {
             what: 'highlightOne',
             selector: selectorFromNode(mouseoverTarget),
@@ -526,21 +517,17 @@ const onMouseOver = (function() {
         });
     };
 
+    const mouseoverTimer = vAPI.defer.create(timerHandler);
+
     return function(ev) {
         if ( inspectedTabId === 0 ) { return; }
         // Convenience: skip real-time highlighting if shift key is pressed.
         if ( ev.shiftKey ) { return; }
         // Find closest `li`
-        var target = ev.target;
+        const target = ev.target.closest('li');
-        while ( target !== null ) {
-            if ( target.localName === 'li' ) { break; }
-            target = target.parentElement;
-        }
         if ( target === mouseoverTarget ) { return; }
         mouseoverTarget = target;
-        if ( mouseoverTimer === null ) {
+        mouseoverTimer.on(50);
-            mouseoverTimer = vAPI.setTimeout(timerHandler, 50);
-        }
     };
 })();
 

src/js/logger-ui.js

@@ -567,8 +567,6 @@ const viewPort = (( ) => {
     let wholeHeight = 0;
     let lastTopPix = 0;
     let lastTopRow = 0;
-    let scrollTimer;
-    let resizeTimer;
 
     const ViewEntry = function() {
         this.div = document.createElement('div');
@@ -602,19 +600,10 @@ const viewPort = (( ) => {
     };
 
     // Coalesce scroll events
-    const onScroll = function() {
+    const scrollTimer = vAPI.defer.create(onScrollChanged);
-        if ( scrollTimer !== undefined ) { return; }
+    const onScroll = ( ) => {
-        scrollTimer = setTimeout(
+        scrollTimer.onvsync(1000/32);
-            ( ) => {
-                scrollTimer = requestAnimationFrame(( ) => {
-                    scrollTimer = undefined;
-                    onScrollChanged();
-                });
-            },
-            1000/32
-        );
     };
-
     dom.on(vwScroller, 'scroll', onScroll, { passive: true });
 
     const onLayoutChanged = function() {
@@ -721,19 +710,10 @@ const viewPort = (( ) => {
         updateContent(0);
     };
 
+    const resizeTimer = vAPI.defer.create(onLayoutChanged);
     const updateLayout = function() {
-        if ( resizeTimer !== undefined ) { return; }
+        resizeTimer.onvsync(1000/8);
-        resizeTimer = setTimeout(
-            ( ) => {
-                resizeTimer = requestAnimationFrame(( ) => {
-                    resizeTimer = undefined;
-                    onLayoutChanged();
-                });
-            },
-            1000/8
-        );
     };
-
     dom.on(window, 'resize', updateLayout, { passive: true });
 
     updateLayout();
@@ -1128,10 +1108,13 @@ const onLogBufferRead = function(response) {
 /******************************************************************************/
 
 const readLogBuffer = (( ) => {
-    let timer;
+    let reading = false;
 
     const readLogBufferNow = async function() {
         if ( logger.ownerId === undefined ) { return; }
+        if ( reading ) { return; }
+
+        reading = true;
 
         const msg = {
             what: 'readAll',
@@ -1159,20 +1142,20 @@ const readLogBuffer = (( ) => {
 
         const response = await vAPI.messaging.send('loggerUI', msg);
 
-        timer = undefined;
         onLogBufferRead(response);
-        readLogBufferLater();
+
+        reading = false;
+
+        timer.on(1200);
     };
 
-    const readLogBufferLater = function() {
+    const timer = vAPI.defer.create(readLogBufferNow);
-        if ( timer !== undefined ) { return; }
-        if ( logger.ownerId === undefined ) { return; }
-        timer = vAPI.setTimeout(readLogBufferNow, 1200);
-    };
 
     readLogBufferNow();
 
-    return readLogBufferLater;
+    return ( ) => {
+        timer.on(1200);
+    };
 })();
  
 /******************************************************************************/
@@ -2203,17 +2186,13 @@ const rowFilterer = (( ) => {
     };
 
     const onFilterChangedAsync = (( ) => {
-        let timer;
         const commit = ( ) => {
-            timer = undefined;
             parseInput();
             filterAll();
         };
+        const timer = vAPI.defer.create(commit);
         return ( ) => {
-            if ( timer !== undefined ) {
+            timer.offon(750);
-                clearTimeout(timer);
-            }
-            timer = vAPI.setTimeout(commit, 750);
         };
     })();
 
@@ -2290,7 +2269,7 @@ const rowJanitor = (( ) => {
 
     let rowIndex = 0;
 
-    const discard = function(timeRemaining) {
+    const discard = function(deadline) {
         const opts = loggerSettings.discard;
         const maxLoadCount = typeof opts.maxLoadCount === 'number'
             ? opts.maxLoadCount
@@ -2301,7 +2280,6 @@ const rowJanitor = (( ) => {
         const obsolete = typeof opts.maxAge === 'number'
             ? Date.now() - opts.maxAge * 60000
             : 0;
-        const deadline = Date.now() + Math.ceil(timeRemaining);
 
         let i = rowIndex;
         // TODO: below should not happen -- remove when confirmed.
@@ -2322,7 +2300,7 @@ const rowJanitor = (( ) => {
 
         while ( i < loggerEntries.length ) {
 
-            if ( i % 64 === 0 && Date.now() >= deadline ) { break; }
+            if ( i % 64 === 0 && deadline.timeRemaining() === 0 ) { break; }
 
             const entry = loggerEntries[i];
             const tabId = entry.tabId || 0;
@@ -2391,18 +2369,15 @@ const rowJanitor = (( ) => {
         rowFilterer.filterAll();
     };
 
-    const discardAsync = function() {
+    const discardAsync = function(deadline) {
-        setTimeout(
+        if ( deadline ) {
-            ( ) => {
+            discard(deadline);
-                self.requestIdleCallback(deadline => {
+        }
-                    discard(deadline.timeRemaining());
+        janitorTimer.onidle(1889);
-                    discardAsync();
-                });
-            },
-            1889
-        );
     };
 
+    const janitorTimer = vAPI.defer.create(discardAsync);
+
     // Clear voided entries from the logger's visible content.
     //
     // Voided entries should be visible only from the "All" option of the
@@ -3030,15 +3005,14 @@ dom.on(window, 'hashchange', pageSelectorFromURLHash);
 // to the window geometry pontentially not settling fast enough.
 if ( self.location.search.includes('popup=1') ) {
     dom.on(window, 'load', ( ) => {
-        setTimeout(
+        vAPI.defer.once(2000).then(( ) => {
-            ( ) => {
+            popupLoggerBox = {
-                popupLoggerBox = {
+                x: self.screenX,
-                    x: self.screenX,
+                y: self.screenY,
-                    y: self.screenY,
+                w: self.outerWidth,
-                    w: self.outerWidth,
+                h: self.outerHeight,
-                    h: self.outerHeight,
+            };
-                };
+        });
-        }, 2000);
     }, { once: true });
 }
 

src/js/logger.js

@@ -27,21 +27,21 @@ let buffer = null;
 let lastReadTime = 0;
 let writePtr = 0;
 
-// After 30 seconds without being read, a buffer will be considered
+// After 30 seconds without being read, the logger buffer will be considered
-// unused, and thus removed from memory.
+// unused, and thus disabled.
 const logBufferObsoleteAfter = 30 * 1000;
 
-const janitor = ( ) => {
+const janitorTimer = vAPI.defer.create(( ) => {
     if ( buffer === null ) { return; }
     if ( lastReadTime >= (Date.now() - logBufferObsoleteAfter) ) {
-        return vAPI.setTimeout(janitor, logBufferObsoleteAfter);
+        return janitorTimer.on(logBufferObsoleteAfter);
     }
     logger.enabled = false;
     buffer = null;
     writePtr = 0;
     logger.ownerId = undefined;
     vAPI.messaging.broadcast({ what: 'loggerDisabled' });
-};
+});
 
 const boxEntry = function(details) {
     if ( details.tstamp === undefined ) {
@@ -68,7 +68,7 @@ const logger = {
         if ( buffer === null ) {
             this.enabled = true;
             buffer = [];
-            vAPI.setTimeout(janitor, logBufferObsoleteAfter);
+            janitorTimer.on(logBufferObsoleteAfter);
         }
         const out = buffer.slice(0, writePtr);
         writePtr = 0;

src/js/lz4.js

@@ -42,7 +42,6 @@ let lz4CodecInstance;
 let pendingInitialization;
 let textEncoder, textDecoder;
 let ttlCount = 0;
-let ttlTimer;
 let ttlDelay = 60000;
 
 const init = function() {
@@ -84,18 +83,16 @@ const destroy = function() {
     lz4CodecInstance = undefined;
     textEncoder = textDecoder = undefined;
     ttlCount = 0;
-    ttlTimer = undefined;
 };
 
+const ttlTimer = vAPI.defer.create(destroy);
+
 const ttlManage = function(count) {
-    if ( ttlTimer !== undefined ) {
+    ttlTimer.off();
-        clearTimeout(ttlTimer);
-        ttlTimer = undefined;
-    }
     ttlCount += count;
     if ( ttlCount > 0 ) { return; }
     if ( lz4CodecInstance === null ) { return; }
-    ttlTimer = vAPI.setTimeout(destroy, ttlDelay);
+    ttlTimer.on(ttlDelay);
 };
 
 const encodeValue = function(dataIn) {

src/js/pagestore.js

@@ -56,6 +56,9 @@ To create a log of net requests
 
 const NetFilteringResultCache = class {
     constructor() {
+        this.pruneTimer = vAPI.defer.create(( ) => {
+            this.prune();
+        });
         this.init();
     }
 
@@ -63,7 +66,6 @@ const NetFilteringResultCache = class {
         this.blocked = new Map();
         this.results = new Map();
         this.hash = 0;
-        this.timer = undefined;
         return this;
     }
 
@@ -111,10 +113,7 @@ const NetFilteringResultCache = class {
         this.blocked.clear();
         this.results.clear();
         this.hash = 0;
-        if ( this.timer !== undefined ) {
+        this.pruneTimer.off();
-            clearTimeout(this.timer);
-            this.timer = undefined;
-        }
     }
 
     prune() {
@@ -136,14 +135,7 @@ const NetFilteringResultCache = class {
     }
 
     pruneAsync() {
-        if ( this.timer !== undefined ) { return; }
+        this.pruneTimer.on(this.shelfLife);
-        this.timer = vAPI.setTimeout(
-            ( ) => {
-                this.timer = undefined;
-                this.prune();
-            },
-            this.shelfLife
-        );
     }
 
     lookupResult(fctxt) {
@@ -353,12 +345,17 @@ const PageStore = class {
     constructor(tabId, details) {
         this.extraData = new Map();
         this.journal = [];
-        this.journalTimer = undefined;
         this.journalLastCommitted = this.journalLastUncommitted = -1;
         this.journalLastUncommittedOrigin = undefined;
         this.netFilteringCache = NetFilteringResultCache.factory();
         this.hostnameDetailsMap = new HostnameDetailsMap();
         this.counts = new CountDetails();
+        this.journalTimer = vAPI.defer.create(( ) => {
+            this.journalProcess();
+        });
+        this.largeMediaTimer = vAPI.defer.create(( ) => {
+            this.injectLargeMediaElementScriptlet();
+        });
         this.init(tabId, details);
     }
 
@@ -398,7 +395,6 @@ const PageStore = class {
         this.remoteFontCount = 0;
         this.popupBlockedCount = 0;
         this.largeMediaCount = 0;
-        this.largeMediaTimer = null;
         this.allowLargeMediaElementsRegex = undefined;
         this.extraData.clear();
 
@@ -441,10 +437,7 @@ const PageStore = class {
         }
 
         // A new page is completely reloaded from scratch, reset all.
-        if ( this.largeMediaTimer !== null ) {
+        this.largeMediaTimer.off();
-            clearTimeout(this.largeMediaTimer);
-            this.largeMediaTimer = null;
-        }
         this.disposeFrameStores();
         this.init(this.tabId, details);
         return this;
@@ -458,15 +451,9 @@ const PageStore = class {
         this.netFilteringCache.empty();
         this.allowLargeMediaElementsUntil = Date.now();
         this.allowLargeMediaElementsRegex = undefined;
-        if ( this.largeMediaTimer !== null ) {
+        this.largeMediaTimer.off();
-            clearTimeout(this.largeMediaTimer);
-            this.largeMediaTimer = null;
-        }
         this.disposeFrameStores();
-        if ( this.journalTimer !== undefined ) {
+        this.journalTimer.off();
-            clearTimeout(this.journalTimer);
-            this.journalTimer = undefined;
-        }
         this.journal = [];
         this.journalLastUncommittedOrigin = undefined;
         this.journalLastCommitted = this.journalLastUncommitted = -1;
@@ -668,11 +655,7 @@ const PageStore = class {
         const hostname = fctxt.getHostname();
         if ( hostname === '' ) { return; }
         this.journal.push(hostname, result, fctxt.itype);
-        if ( this.journalTimer !== undefined ) { return; }
+        this.journalTimer.on(µb.hiddenSettings.requestJournalProcessPeriod);
-        this.journalTimer = vAPI.setTimeout(
-            ( ) => { this.journalProcess(true); },
-            µb.hiddenSettings.requestJournalProcessPeriod
-        );
     }
 
     journalAddRootFrame(type, url) {
@@ -695,18 +678,11 @@ const PageStore = class {
                 this.journalLastUncommittedOrigin = newOrigin;
             }
         }
-        if ( this.journalTimer !== undefined ) {
+        this.journalTimer.offon(µb.hiddenSettings.requestJournalProcessPeriod);
-            clearTimeout(this.journalTimer);
-        }
-        this.journalTimer = vAPI.setTimeout(
-            ( ) => { this.journalProcess(true); },
-            µb.hiddenSettings.requestJournalProcessPeriod
-        );
     }
 
-    journalProcess(fromTimer = false) {
+    journalProcess() {
-        if ( fromTimer === false ) { clearTimeout(this.journalTimer); }
+        this.journalTimer.off();
-        this.journalTimer = undefined;
 
         const journal = this.journal;
         const pivot = Math.max(0, this.journalLastCommitted);
@@ -1058,12 +1034,7 @@ const PageStore = class {
         }
 
         this.largeMediaCount += 1;
-        if ( this.largeMediaTimer === null ) {
+        this.largeMediaTimer.on(500);
-            this.largeMediaTimer = vAPI.setTimeout(( ) => {
-                this.largeMediaTimer = null;
-                this.injectLargeMediaElementScriptlet();
-            }, 500);
-        }
 
         if ( logger.enabled ) {
             fctxt.filter = sessionSwitches.toLogData();

src/js/popup-fenix.js

@@ -1376,29 +1376,23 @@ const toggleHostnameSwitch = async function(ev) {
 // it and thus having to push it all the time unconditionally.
 
 const pollForContentChange = (( ) => {
-    let pollTimer;
-
     const pollCallback = async function() {
-        pollTimer = undefined;
         const response = await messaging.send('popupPanel', {
             what: 'hasPopupContentChanged',
             tabId: popupData.tabId,
             contentLastModified: popupData.contentLastModified,
         });
-        queryCallback(response);
-    };
-
-    const queryCallback = function(response) {
         if ( response ) {
-            getPopupData(popupData.tabId);
+            await getPopupData(popupData.tabId);
             return;
         }
         poll();
     };
 
+    const pollTimer = vAPI.defer.create(pollCallback);
+
     const poll = function() {
-        if ( pollTimer !== undefined ) { return; }
+        pollTimer.on(1500);
-        pollTimer = vAPI.setTimeout(pollCallback, 1500);
     };
 
     return poll;

src/js/reverselookup.js

@@ -36,11 +36,9 @@ import {
 
 /******************************************************************************/
 
-const workerTTL = 5 * 60 * 1000;
 const pendingResponses = new Map();
 
 let worker = null;
-let workerTTLTimer;
 let needLists = true;
 let messageId = 1;
 
@@ -52,10 +50,7 @@ const onWorkerMessage = function(e) {
 };
 
 const stopWorker = function() {
-    if ( workerTTLTimer !== undefined ) {
+    stopWorker.off();
-        clearTimeout(workerTTLTimer);
-        workerTTLTimer = undefined;
-    }
     if ( worker === null ) { return; }
     worker.terminate();
     worker = null;
@@ -66,6 +61,9 @@ const stopWorker = function() {
     pendingResponses.clear();
 };
 
+const workerTTLTimer = vAPI.defer.create(stopWorker);
+const workerTTL = { min: 5 };
+
 const initWorker = function() {
     if ( worker === null ) {
         worker = new Worker('js/reverselookup-worker.js');
@@ -73,10 +71,7 @@ const initWorker = function() {
     }
 
     // The worker will be shutdown after n minutes without being used.
-    if ( workerTTLTimer !== undefined ) {
+    workerTTLTimer.offon(workerTTL);
-        clearTimeout(workerTTLTimer);
-    }
-    workerTTLTimer = vAPI.setTimeout(stopWorker, workerTTL);
 
     if ( needLists === false ) {
         return Promise.resolve();

src/js/storage.js

@@ -98,23 +98,26 @@ import {
 
 /******************************************************************************/
 
-µb.saveLocalSettings = (( ) => {
+{
-    const saveAfter = 4 * 60 * 1000;
+    let localSettingsLastSaved = Date.now();
 
-    const onTimeout = ( ) => {
+    const shouldSave = ( ) => {
-        if ( µb.localSettingsLastModified > µb.localSettingsLastSaved ) {
+        if ( µb.localSettingsLastModified > localSettingsLastSaved ) {
             µb.saveLocalSettings();
         }
-        vAPI.setTimeout(onTimeout, saveAfter);
+        saveTimer.on(saveDelay);
     };
 
-    vAPI.setTimeout(onTimeout, saveAfter);
+    const saveTimer = vAPI.defer.create(shouldSave);
+    const saveDelay = { min: 4 };
 
-    return function() {
+    saveTimer.on(saveDelay);
-        this.localSettingsLastSaved = Date.now();
+
+    µb.saveLocalSettings = function() {
+        localSettingsLastSaved = Date.now();
         return vAPI.storage.set(this.localSettings);
     };
-})();
+}
 
 /******************************************************************************/
 
@@ -1445,15 +1448,17 @@ self.addEventListener('hiddenSettingsChanged', ( ) => {
 /******************************************************************************/
 
 {
-    let timer, next = 0;
+    let next = 0;
     let lastEmergencyUpdate = 0;
 
-    µb.scheduleAssetUpdater = async function(updateDelay) {
+    const launchTimer = vAPI.defer.create(fetchDelay => {
+        next = 0;
+        io.updateStart({ delay: fetchDelay, auto: true });
+    });
+
+    µb.scheduleAssetUpdater = async function(updateDelay) {
+        launchTimer.off();
 
-        if ( timer ) {
-            clearTimeout(timer);
-            timer = undefined;
-        }
         if ( updateDelay === 0 ) {
             next = 0;
             return;
@@ -1499,11 +1504,7 @@ self.addEventListener('hiddenSettingsChanged', ( ) => {
             ? 2000
             : this.hiddenSettings.autoUpdateAssetFetchPeriod * 1000 || 60000;
 
-        timer = vAPI.setTimeout(( ) => {
+        launchTimer.on(updateDelay, fetchDelay);
-            timer = undefined;
-            next = 0;
-            io.updateStart({ delay: fetchDelay, auto: true });
-        }, updateDelay);
     };
 }
 

src/js/tab.js

@@ -515,25 +515,19 @@ housekeep itself.
                     ? µb.maybeGoodPopup.url
                     : ''
             };
-            this.selfDestructionTimer = null;
+            this.selfDestructionTimer = vAPI.defer.create(( ) => {
+                this.destroy();
+            });
             this.launchSelfDestruction();
         }
 
         destroy() {
-            if ( this.selfDestructionTimer !== null ) {
+            this.selfDestructionTimer.off();
-                clearTimeout(this.selfDestructionTimer);
-            }
             popupCandidates.delete(this.targetTabId);
         }
 
         launchSelfDestruction() {
-            if ( this.selfDestructionTimer !== null ) {
+            this.selfDestructionTimer.offon(10000);
-                clearTimeout(this.selfDestructionTimer);
-            }
-            this.selfDestructionTimer = vAPI.setTimeout(
-                ( ) => this.destroy(),
-                10000
-            );
         }
     };
 
@@ -618,8 +612,12 @@ housekeep itself.
         this.origin =
         this.rootHostname =
         this.rootDomain = '';
-        this.commitTimer = null;
+        this.commitTimer = vAPI.defer.create(( ) => {
-        this.gcTimer = null;
+            this.onCommit();
+        });
+        this.gcTimer = vAPI.defer.create(( ) => {
+            this.onGC();
+        });
         this.onGCBarrier = false;
         this.netFiltering = true;
         this.netFilteringReadTime = 0;
@@ -629,28 +627,20 @@ housekeep itself.
 
     TabContext.prototype.destroy = function() {
         if ( vAPI.isBehindTheSceneTabId(this.tabId) ) { return; }
-        if ( this.gcTimer !== null ) {
+        this.gcTimer.off();
-            clearTimeout(this.gcTimer);
-            this.gcTimer = null;
-        }
         tabContexts.delete(this.tabId);
     };
 
     TabContext.prototype.onGC = async function() {
         if ( vAPI.isBehindTheSceneTabId(this.tabId) ) { return; }
-        // https://github.com/gorhill/uBlock/issues/1713
-        //   For unknown reasons, Firefox's setTimeout() will sometimes
-        //   causes the callback function to be called immediately, bypassing
-        //   the main event loop. For now this should prevent uBO from
-        //   crashing as a result of the bad setTimeout() behavior.
         if ( this.onGCBarrier ) { return; }
         this.onGCBarrier = true;
-        this.gcTimer = null;
+        this.gcTimer.off();
         const tab = await vAPI.tabs.get(this.tabId);
         if ( tab instanceof Object === false || tab.discarded === true ) {
             this.destroy();
         } else {
-            this.gcTimer = vAPI.setTimeout(( ) => this.onGC(), gcPeriod);
+            this.gcTimer.on(gcPeriod);
         }
         this.onGCBarrier = false;
     };
@@ -659,10 +649,8 @@ housekeep itself.
     // Stack entries have to be committed to stick. Non-committed stack
     // entries are removed after a set delay.
     TabContext.prototype.onCommit = function() {
-        if ( vAPI.isBehindTheSceneTabId(this.tabId) ) {
+        if ( vAPI.isBehindTheSceneTabId(this.tabId) ) { return; }
-            return;
+        this.commitTimer.off();
-        }
-        this.commitTimer = null;
         // Remove uncommitted entries at the top of the stack.
         let i = this.stack.length;
         while ( i-- ) {
@@ -687,7 +675,7 @@ housekeep itself.
     // want to flush it.
     TabContext.prototype.autodestroy = function() {
         if ( vAPI.isBehindTheSceneTabId(this.tabId) ) { return; }
-        this.gcTimer = vAPI.setTimeout(( ) => this.onGC(), gcPeriod);
+        this.gcTimer.on(gcPeriod);
     };
 
     // Update just force all properties to be updated to match the most recent
@@ -727,10 +715,7 @@ housekeep itself.
         this.stack.push(new StackEntry(url));
         this.update();
         popupCandidateTest(this.tabId);
-        if ( this.commitTimer !== null ) {
+        this.commitTimer.offon(500);
-            clearTimeout(this.commitTimer);
-        }
-        this.commitTimer = vAPI.setTimeout(( ) => this.onCommit(), 500);
     };
 
     // This tells that the url is definitely the one to be associated with the
@@ -1156,7 +1141,6 @@ vAPI.tabs = new vAPI.Tabs();
 //   Stale page store entries janitor
 
 {
-    const pageStoreJanitorPeriod = 15 * 60 * 1000;
     let pageStoreJanitorSampleAt = 0;
     let pageStoreJanitorSampleSize = 10;
 
@@ -1182,10 +1166,13 @@ vAPI.tabs = new vAPI.Tabs();
         }
         pageStoreJanitorSampleAt = n;
 
-        vAPI.setTimeout(pageStoreJanitor, pageStoreJanitorPeriod);
+        pageStoreJanitorTimer.on(pageStoreJanitorPeriod);
     };
 
-    vAPI.setTimeout(pageStoreJanitor, pageStoreJanitorPeriod);
+    const pageStoreJanitorTimer = vAPI.defer.create(pageStoreJanitor);
+    const pageStoreJanitorPeriod = { min: 15 };
+
+    pageStoreJanitorTimer.on(pageStoreJanitorPeriod);
 }
 
 /******************************************************************************/

src/js/traffic.js

@@ -439,23 +439,23 @@ const onBeforeBehindTheSceneRequest = function(fctxt) {
 //   request.
 
 {
+    const pageStores = new Set();
     let hostname = '';
-    let pageStores = new Set();
     let pageStoresToken = 0;
-    let gcTimer;
 
     const reset = function() {
         hostname = '';
-        pageStores = new Set();
+        pageStores.clear();
         pageStoresToken = 0;
     };
 
     const gc = ( ) => {
-        gcTimer = undefined;
         if ( pageStoresToken !== µb.pageStoresToken ) { return reset(); }
-        gcTimer = vAPI.setTimeout(gc, 30011);
+        gcTimer.on(30011);
     };
 
+    const gcTimer = vAPI.defer.create(gc);
+
     onBeforeBehindTheSceneRequest.journalAddRequest = (fctxt, result) => {
         const docHostname = fctxt.getDocHostname();
         if (
@@ -463,16 +463,13 @@ const onBeforeBehindTheSceneRequest = function(fctxt) {
             pageStoresToken !== µb.pageStoresToken
         ) {
             hostname = docHostname;
-            pageStores = new Set();
+            pageStores.clear();
             for ( const pageStore of µb.pageStores.values() ) {
                 if ( pageStore.tabHostname !== docHostname ) { continue; }
                 pageStores.add(pageStore);
             }
             pageStoresToken = µb.pageStoresToken;
-            if ( gcTimer !== undefined ) {
+            gcTimer.offon(30011);
-                clearTimeout(gcTimer);
-            }
-            gcTimer = vAPI.setTimeout(gc, 30011);
         }
         for ( const pageStore of pageStores ) {
             pageStore.journalAddRequest(fctxt, result);
@@ -1057,7 +1054,9 @@ const headerValueFromName = function(headerName, headers) {
 
 const strictBlockBypasser = {
     hostnameToDeadlineMap: new Map(),
-    cleanupTimer: undefined,
+    cleanupTimer: vAPI.defer.create(( ) => {
+        strictBlockBypasser.cleanup();
+    }),
 
     cleanup: function() {
         for ( const [ hostname, deadline ] of this.hostnameToDeadlineMap ) {
@@ -1067,35 +1066,23 @@ const strictBlockBypasser = {
         }
     },
 
+    revokeTime: function() {
+        return Date.now() + µb.hiddenSettings.strictBlockingBypassDuration * 1000;
+    },
+
     bypass: function(hostname) {
         if ( typeof hostname !== 'string' || hostname === '' ) { return; }
-        this.hostnameToDeadlineMap.set(
+        this.hostnameToDeadlineMap.set(hostname, this.revokeTime());
-            hostname,
-            Date.now() + µb.hiddenSettings.strictBlockingBypassDuration * 1000
-        );
     },
 
     isBypassed: function(hostname) {
         if ( this.hostnameToDeadlineMap.size === 0 ) { return false; }
-        let bypassDuration =
+        this.cleanupTimer.on({ sec: µb.hiddenSettings.strictBlockingBypassDuration + 10 });
-            µb.hiddenSettings.strictBlockingBypassDuration * 1000;
-        if ( this.cleanupTimer === undefined ) {
-            this.cleanupTimer = vAPI.setTimeout(
-                ( ) => {
-                    this.cleanupTimer = undefined;
-                    this.cleanup();
-                },
-                bypassDuration + 10000
-            );
-        }
         for (;;) {
             const deadline = this.hostnameToDeadlineMap.get(hostname);
             if ( deadline !== undefined ) {
                 if ( deadline > Date.now() ) {
-                    this.hostnameToDeadlineMap.set(
+                    this.hostnameToDeadlineMap.set(hostname, this.revokeTime());
-                        hostname,
-                        Date.now() + bypassDuration
-                    );
                     return true;
                 }
                 this.hostnameToDeadlineMap.delete(hostname);