Use .bind instead of () => {}

ext/bg/js/backend.js

@@ -100,10 +100,10 @@ class Backend {
         this.onOptionsUpdated('background');
 
         if (isObject(chrome.commands) && isObject(chrome.commands.onCommand)) {
-            chrome.commands.onCommand.addListener((command) => this._runCommand(command));
+            chrome.commands.onCommand.addListener(this._runCommand.bind(this));
         }
         if (isObject(chrome.tabs) && isObject(chrome.tabs.onZoomChange)) {
-            chrome.tabs.onZoomChange.addListener((info) => this._onZoomChange(info));
+            chrome.tabs.onZoomChange.addListener(this._onZoomChange.bind(this));
         }
         chrome.runtime.onMessage.addListener(this.onMessage.bind(this));
 
@@ -116,7 +116,7 @@ class Backend {
         this.isPreparedResolve = null;
         this.isPreparedPromise = null;
 
-        this.clipboardMonitor.onClipboardText = (text) => this._onClipboardText(text);
+        this.clipboardMonitor.onClipboardText = this._onClipboardText.bind(this);
     }
 
     onOptionsUpdated(source) {

ext/bg/js/search.js

@@ -93,18 +93,18 @@ class DisplaySearch extends Display {
                 } else {
                     this.clipboardMonitorEnable.checked = false;
                 }
-                this.clipboardMonitorEnable.addEventListener('change', (e) => this.onClipboardMonitorEnableChange(e));
+                this.clipboardMonitorEnable.addEventListener('change', this.onClipboardMonitorEnableChange.bind(this));
             }
 
             chrome.runtime.onMessage.addListener(this.onRuntimeMessage.bind(this));
 
-            this.search.addEventListener('click', (e) => this.onSearch(e), false);
+            this.search.addEventListener('click', this.onSearch.bind(this), false);
-            this.query.addEventListener('input', () => this.onSearchInput(), false);
+            this.query.addEventListener('input', this.onSearchInput.bind(this), false);
-            this.wanakanaEnable.addEventListener('change', (e) => this.onWanakanaEnableChange(e));
+            this.wanakanaEnable.addEventListener('change', this.onWanakanaEnableChange.bind(this));
-            window.addEventListener('popstate', (e) => this.onPopState(e));
+            window.addEventListener('popstate', this.onPopState.bind(this));
-            window.addEventListener('copy', (e) => this.onCopy(e));
+            window.addEventListener('copy', this.onCopy.bind(this));
 
-            this.clipboardMonitor.onClipboardText = (text) => this.onExternalSearchUpdate(text);
+            this.clipboardMonitor.onClipboardText = this.onExternalSearchUpdate.bind(this);
 
             this.updateSearchButton();
         } catch (e) {

ext/bg/js/settings/audio-ui.js

@@ -37,7 +37,7 @@ AudioSourceUI.Container = class Container {
             this.children.push(new AudioSourceUI.AudioSource(this, audioSource, this.children.length));
         }
 
-        this._clickListener = () => this.onAddAudioSource();
+        this._clickListener = this.onAddAudioSource.bind(this);
         this.addButton.addEventListener('click', this._clickListener, false);
     }
 
@@ -105,8 +105,8 @@ AudioSourceUI.AudioSource = class AudioSource {
 
         this.select.value = audioSource;
 
-        this._selectChangeListener = () => this.onSelectChanged();
+        this._selectChangeListener = this.onSelectChanged.bind(this);
-        this._removeClickListener = () => this.onRemoveClicked();
+        this._removeClickListener = this.onRemoveClicked.bind(this);
 
         this.select.addEventListener('change', this._selectChangeListener, false);
         this.removeButton.addEventListener('click', this._removeClickListener, false);

ext/bg/js/settings/conditions-ui.js

@@ -41,7 +41,7 @@ ConditionsUI.Container = class Container {
             this.children.push(new ConditionsUI.ConditionGroup(this, conditionGroup));
         }
 
-        this.addButton.on('click', () => this.onAddConditionGroup());
+        this.addButton.on('click', this.onAddConditionGroup.bind(this));
     }
 
     cleanup() {
@@ -127,7 +127,7 @@ ConditionsUI.ConditionGroup = class ConditionGroup {
             this.children.push(new ConditionsUI.Condition(this, condition));
         }
 
-        this.addButton.on('click', () => this.onAddCondition());
+        this.addButton.on('click', this.onAddCondition.bind(this));
     }
 
     cleanup() {
@@ -185,10 +185,10 @@ ConditionsUI.Condition = class Condition {
         this.updateOperators();
         this.updateInput();
 
-        this.input.on('change', () => this.onInputChanged());
+        this.input.on('change', this.onInputChanged.bind(this));
-        this.typeSelect.on('change', () => this.onConditionTypeChanged());
+        this.typeSelect.on('change', this.onConditionTypeChanged.bind(this));
-        this.operatorSelect.on('change', () => this.onConditionOperatorChanged());
+        this.operatorSelect.on('change', this.onConditionOperatorChanged.bind(this));
-        this.removeButton.on('click', () => this.onRemoveClicked());
+        this.removeButton.on('click', this.onRemoveClicked.bind(this));
     }
 
     cleanup() {

ext/bg/js/settings/dictionaries.js

@@ -36,7 +36,7 @@ class SettingsDictionaryListUI {
         this.dictionaryEntries = [];
         this.extra = null;
 
-        document.querySelector('#dict-delete-confirm').addEventListener('click', (e) => this.onDictionaryConfirmDelete(e), false);
+        document.querySelector('#dict-delete-confirm').addEventListener('click', this.onDictionaryConfirmDelete.bind(this), false);
     }
 
     setOptionsDictionaries(optionsDictionaries) {
@@ -198,10 +198,10 @@ class SettingsDictionaryEntryUI {
 
         this.applyValues();
 
-        this.eventListeners.addEventListener(this.enabledCheckbox, 'change', (e) => this.onEnabledChanged(e), false);
+        this.eventListeners.addEventListener(this.enabledCheckbox, 'change', this.onEnabledChanged.bind(this), false);
-        this.eventListeners.addEventListener(this.allowSecondarySearchesCheckbox, 'change', (e) => this.onAllowSecondarySearchesChanged(e), false);
+        this.eventListeners.addEventListener(this.allowSecondarySearchesCheckbox, 'change', this.onAllowSecondarySearchesChanged.bind(this), false);
-        this.eventListeners.addEventListener(this.priorityInput, 'change', (e) => this.onPriorityChanged(e), false);
+        this.eventListeners.addEventListener(this.priorityInput, 'change', this.onPriorityChanged.bind(this), false);
-        this.eventListeners.addEventListener(this.deleteButton, 'click', (e) => this.onDeleteButtonClicked(e), false);
+        this.eventListeners.addEventListener(this.deleteButton, 'click', this.onDeleteButtonClicked.bind(this), false);
     }
 
     cleanup() {

ext/bg/js/settings/popup-preview-frame.js

@@ -44,7 +44,7 @@ class SettingsPopupPreview {
 
     async prepare() {
         // Setup events
-        window.addEventListener('message', (e) => this.onMessage(e), false);
+        window.addEventListener('message', this.onMessage.bind(this), false);
 
         const themeDarkCheckbox = document.querySelector('#theme-dark-checkbox');
         if (themeDarkCheckbox !== null) {
@@ -52,7 +52,7 @@ class SettingsPopupPreview {
         }
 
         // Overwrite API functions
-        window.apiOptionsGet = (...args) => this.apiOptionsGet(...args);
+        window.apiOptionsGet = this.apiOptionsGet.bind(this);
 
         // Overwrite frontend
         const popupHost = new PopupProxyHost();
@@ -62,7 +62,7 @@ class SettingsPopupPreview {
         this.popup.setChildrenSupported(false);
 
         this.popupSetCustomOuterCssOld = this.popup.setCustomOuterCss;
-        this.popup.setCustomOuterCss = (...args) => this.popupSetCustomOuterCss(...args);
+        this.popup.setCustomOuterCss = this.popupSetCustomOuterCss.bind(this);
 
         this.frontend = new Frontend(this.popup);
 

ext/fg/js/float.js

@@ -51,8 +51,8 @@ class DisplayFloat extends Display {
             ['setContentScale', ({scale}) => this.setContentScale(scale)]
         ]);
 
-        yomichan.on('orphaned', () => this.onOrphaned());
+        yomichan.on('orphaned', this.onOrphaned.bind(this));
-        window.addEventListener('message', (e) => this.onMessage(e), false);
+        window.addEventListener('message', this.onMessage.bind(this), false);
     }
 
     async prepare(options, popupInfo, url, childrenSupported, scale, uniqueId) {

ext/fg/js/frontend.js

@@ -64,9 +64,9 @@ class Frontend extends TextScanner {
                 window.visualViewport.addEventListener('resize', this.onVisualViewportResize.bind(this));
             }
 
-            yomichan.on('orphaned', () => this.onOrphaned());
+            yomichan.on('orphaned', this.onOrphaned.bind(this));
-            yomichan.on('optionsUpdated', () => this.updateOptions());
+            yomichan.on('optionsUpdated', this.updateOptions.bind(this));
-            yomichan.on('zoomChanged', (e) => this.onZoomChanged(e));
+            yomichan.on('zoomChanged', this.onZoomChanged.bind(this));
             chrome.runtime.onMessage.addListener(this.onRuntimeMessage.bind(this));
 
             this._updateContentScale();

ext/fg/js/popup.js

@@ -260,7 +260,7 @@ class Popup {
             'mozfullscreenchange',
             'webkitfullscreenchange'
         ];
-        const onFullscreenChanged = () => this._onFullscreenChanged();
+        const onFullscreenChanged = this._onFullscreenChanged.bind(this);
         for (const eventName of fullscreenEvents) {
             this._fullscreenEventListeners.addEventListener(document, eventName, onFullscreenChanged, false);
         }

ext/mixed/js/scroll.js

@@ -26,7 +26,7 @@ class WindowScroll {
         this.animationEndTime = 0;
         this.animationEndX = 0;
         this.animationEndY = 0;
-        this.requestAnimationFrameCallback = (t) => this.onAnimationFrame(t);
+        this.requestAnimationFrameCallback = this.onAnimationFrame.bind(this);
     }
 
     toY(y) {