Remove the internal "secondarytoolbarreset" event and slightly re-factor the code

With modern JavaScript class features we can move the relevant event handling into private methods, and thus invoke it directly when resetting the toolbar UI-state.

*Please note:* This patch slightly reduces the size of the `web/secondary_toolbar.js` file.

web/secondary_toolbar.js

@@ -52,14 +52,15 @@ import { PagesCountLimit } from "./pdf_viewer.js";
  */
 
 class SecondaryToolbar {
+  #opts;
+
   /**
    * @param {SecondaryToolbarOptions} options
    * @param {EventBus} eventBus
    */
   constructor(options, eventBus) {
-    this.toolbar = options.toolbar;
+    this.#opts = options;
-    this.toggleButton = options.toggleButton;
+    const buttons = [
-    this.buttons = [
       {
         element: options.presentationModeButton,
         eventName: "presentationmode",
@@ -141,28 +142,19 @@ class SecondaryToolbar {
       },
     ];
     if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
-      this.buttons.push({
+      buttons.push({
         element: options.openFileButton,
         eventName: "openfile",
         close: true,
       });
     }
-    this.items = {
-      firstPage: options.firstPageButton,
-      lastPage: options.lastPageButton,
-      pageRotateCw: options.pageRotateCwButton,
-      pageRotateCcw: options.pageRotateCcwButton,
-    };
 
     this.eventBus = eventBus;
     this.opened = false;
 
     // Bind the event listeners for click, cursor tool, and scroll/spread mode
     // actions.
-    this.#bindClickListeners();
+    this.#bindListeners(buttons);
-    this.#bindCursorToolsListener(options);
-    this.#bindScrollModeListener(options);
-    this.#bindSpreadModeListener(options);
 
     this.reset();
   }
@@ -190,30 +182,40 @@ class SecondaryToolbar {
     this.#updateUIState();
 
     // Reset the Scroll/Spread buttons too, since they're document specific.
-    this.eventBus.dispatch("secondarytoolbarreset", { source: this });
+    this.#scrollModeChanged({ mode: ScrollMode.VERTICAL });
+    this.#spreadModeChanged({ mode: SpreadMode.NONE });
   }
 
   #updateUIState() {
-    this.items.firstPage.disabled = this.pageNumber <= 1;
+    const {
-    this.items.lastPage.disabled = this.pageNumber >= this.pagesCount;
+      firstPageButton,
-    this.items.pageRotateCw.disabled = this.pagesCount === 0;
+      lastPageButton,
-    this.items.pageRotateCcw.disabled = this.pagesCount === 0;
+      pageRotateCwButton,
+      pageRotateCcwButton,
+    } = this.#opts;
+
+    firstPageButton.disabled = this.pageNumber <= 1;
+    lastPageButton.disabled = this.pageNumber >= this.pagesCount;
+    pageRotateCwButton.disabled = this.pagesCount === 0;
+    pageRotateCcwButton.disabled = this.pagesCount === 0;
   }
 
-  #bindClickListeners() {
+  #bindListeners(buttons) {
+    const { eventBus } = this;
+    const { toggleButton } = this.#opts;
     // Button to toggle the visibility of the secondary toolbar.
-    this.toggleButton.addEventListener("click", this.toggle.bind(this));
+    toggleButton.addEventListener("click", this.toggle.bind(this));
 
     // All items within the secondary toolbar.
-    for (const { element, eventName, close, eventDetails } of this.buttons) {
+    for (const { element, eventName, close, eventDetails } of buttons) {
       element.addEventListener("click", evt => {
         if (eventName !== null) {
-          this.eventBus.dispatch(eventName, { source: this, ...eventDetails });
+          eventBus.dispatch(eventName, { source: this, ...eventDetails });
         }
         if (close) {
           this.close();
         }
-        this.eventBus.dispatch("reporttelemetry", {
+        eventBus.dispatch("reporttelemetry", {
           source: this,
           details: {
             type: "buttons",
@@ -222,16 +224,21 @@ class SecondaryToolbar {
         });
       });
     }
+
+    eventBus._on("cursortoolchanged", this.#cursorToolChanged.bind(this));
+    eventBus._on("scrollmodechanged", this.#scrollModeChanged.bind(this));
+    eventBus._on("spreadmodechanged", this.#spreadModeChanged.bind(this));
   }
 
-  #bindCursorToolsListener({ cursorSelectToolButton, cursorHandToolButton }) {
+  #cursorToolChanged({ tool }) {
-    this.eventBus._on("cursortoolchanged", ({ tool }) => {
+    const { cursorSelectToolButton, cursorHandToolButton } = this.#opts;
+
     toggleCheckedBtn(cursorSelectToolButton, tool === CursorTool.SELECT);
     toggleCheckedBtn(cursorHandToolButton, tool === CursorTool.HAND);
-    });
   }
 
-  #bindScrollModeListener({
+  #scrollModeChanged({ mode }) {
+    const {
       scrollPageButton,
       scrollVerticalButton,
       scrollHorizontalButton,
@@ -239,8 +246,8 @@ class SecondaryToolbar {
       spreadNoneButton,
       spreadOddButton,
       spreadEvenButton,
-  }) {
+    } = this.#opts;
-    const scrollModeChanged = ({ mode }) => {
+
     toggleCheckedBtn(scrollPageButton, mode === ScrollMode.PAGE);
     toggleCheckedBtn(scrollVerticalButton, mode === ScrollMode.VERTICAL);
     toggleCheckedBtn(scrollHorizontalButton, mode === ScrollMode.HORIZONTAL);
@@ -261,33 +268,14 @@ class SecondaryToolbar {
     spreadNoneButton.disabled = isHorizontal;
     spreadOddButton.disabled = isHorizontal;
     spreadEvenButton.disabled = isHorizontal;
-    };
-    this.eventBus._on("scrollmodechanged", scrollModeChanged);
-
-    this.eventBus._on("secondarytoolbarreset", evt => {
-      if (evt.source === this) {
-        scrollModeChanged({ mode: ScrollMode.VERTICAL });
-      }
-    });
   }
 
-  #bindSpreadModeListener({
+  #spreadModeChanged({ mode }) {
-    spreadNoneButton,
+    const { spreadNoneButton, spreadOddButton, spreadEvenButton } = this.#opts;
-    spreadOddButton,
+
-    spreadEvenButton,
-  }) {
-    const spreadModeChanged = ({ mode }) => {
     toggleCheckedBtn(spreadNoneButton, mode === SpreadMode.NONE);
     toggleCheckedBtn(spreadOddButton, mode === SpreadMode.ODD);
     toggleCheckedBtn(spreadEvenButton, mode === SpreadMode.EVEN);
-    };
-    this.eventBus._on("spreadmodechanged", spreadModeChanged);
-
-    this.eventBus._on("secondarytoolbarreset", evt => {
-      if (evt.source === this) {
-        spreadModeChanged({ mode: SpreadMode.NONE });
-      }
-    });
   }
 
   open() {
@@ -295,7 +283,9 @@ class SecondaryToolbar {
       return;
     }
     this.opened = true;
-    toggleExpandedBtn(this.toggleButton, true, this.toolbar);
+
+    const { toggleButton, toolbar } = this.#opts;
+    toggleExpandedBtn(toggleButton, true, toolbar);
   }
 
   close() {
@@ -303,7 +293,9 @@ class SecondaryToolbar {
       return;
     }
     this.opened = false;
-    toggleExpandedBtn(this.toggleButton, false, this.toolbar);
+
+    const { toggleButton, toolbar } = this.#opts;
+    toggleExpandedBtn(toggleButton, false, toolbar);
   }
 
   toggle() {