From 54410d5e4189d1773db4df1d20bbcd93cafae756 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 4 May 2022 11:35:04 +0200
Subject: [PATCH] Simplify the signature of `BaseViewer._scrollIntoView` and
 make the method private

In PR 14112 usage of this *internal* method was reduced, and it thus can't hurt to clean-up things a little bit more.
Note in particular that we can simplify the call-sites by directly passing in the already available `PDFPageView`-instance, since the `id`-property those contain can replace the previous `pageNumber`-parameter[1].

Given that the method name has always been prefixed with an underscore it was thus never intended to be "public", hence we can now enforce that with modern ECMAScript features.

---
[1] There's already a bunch of other spots, throughout the viewer-code, where we assume that the `PDFPageView.id`-property contains proper page *numbers* (and not e.g. indices); note how we initialize the `PDFPageView`-instances in the `BaseViewer.setDocument`-method.
---
 web/base_viewer.js | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/web/base_viewer.js b/web/base_viewer.js
index 284deb331..042355128 100644
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@@ -943,10 +943,12 @@ class BaseViewer {
     this.update();
   }
 
-  _scrollIntoView({ pageDiv, pageNumber, pageSpot = null }) {
+  #scrollIntoView(pageView, pageSpot = null) {
+    const { div, id } = pageView;
+
     if (this._scrollMode === ScrollMode.PAGE) {
       // Ensure that `this._currentPageNumber` is correct.
-      this._setCurrentPageNumber(pageNumber);
+      this._setCurrentPageNumber(id);
 
       this.#ensurePageViewVisible();
       // Ensure that rendering always occurs, to avoid showing a blank page,
@@ -955,8 +957,8 @@ class BaseViewer {
     }
 
     if (!pageSpot && !this.isInPresentationMode) {
-      const left = pageDiv.offsetLeft + pageDiv.clientLeft;
-      const right = left + pageDiv.clientWidth;
+      const left = div.offsetLeft + div.clientLeft,
+        right = left + div.clientWidth;
       const { scrollLeft, clientWidth } = this.container;
       if (
         this._scrollMode === ScrollMode.HORIZONTAL ||
@@ -966,7 +968,7 @@ class BaseViewer {
         pageSpot = { left: 0, top: 0 };
       }
     }
-    scrollIntoView(pageDiv, pageSpot);
+    scrollIntoView(div, pageSpot);
   }
 
   /**
@@ -1120,15 +1122,13 @@ class BaseViewer {
    * Refreshes page view: scrolls to the current page and updates the scale.
    */
   #resetCurrentPageView() {
-    const pageNumber = this._currentPageNumber;
+    const pageView = this._pages[this._currentPageNumber - 1];
 
     if (this.isInPresentationMode) {
       // Fixes the case when PDF has different page sizes.
       this._setScale(this._currentScaleValue, true);
     }
-
-    const pageView = this._pages[pageNumber - 1];
-    this._scrollIntoView({ pageDiv: pageView.div, pageNumber });
+    this.#scrollIntoView(pageView);
   }
 
   /**
@@ -1272,10 +1272,7 @@ class BaseViewer {
     }
 
     if (scale === "page-fit" && !destArray[4]) {
-      this._scrollIntoView({
-        pageDiv: pageView.div,
-        pageNumber,
-      });
+      this.#scrollIntoView(pageView);
       return;
     }
 
@@ -1293,11 +1290,7 @@ class BaseViewer {
       left = Math.max(left, 0);
       top = Math.max(top, 0);
     }
-    this._scrollIntoView({
-      pageDiv: pageView.div,
-      pageSpot: { left, top },
-      pageNumber,
-    });
+    this.#scrollIntoView(pageView, /* pageSpot = */ { left, top });
   }
 
   _updateLocation(firstPage) {