From 8bbb7c88d3936df33fda7fa5536f5dd4a21f6cf3 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Mon, 9 Mar 2026 16:11:21 +0100
Subject: [PATCH 1/2] Change the
 `AnnotationLayer.prototype.getEditableAnnotations` method to return an
 iterator

This method is only used with loops, and it should be a tiny bit more efficient to use an iterator directly rather than first iterating through the underlying `Map` to create a temporary `Array` that we finally iterate through at the call-site.
---
 src/display/annotation_layer.js               | 2 +-
 src/display/editor/annotation_editor_layer.js | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/display/annotation_layer.js b/src/display/annotation_layer.js
index 7a992484605d4..d131b145a7e11 100644
--- a/src/display/annotation_layer.js
+++ b/src/display/annotation_layer.js
@@ -4100,7 +4100,7 @@ class AnnotationLayer {
   }
 
   getEditableAnnotations() {
-    return Array.from(this.#editableAnnotations.values());
+    return this.#editableAnnotations.values();
   }
 
   getEditableAnnotation(id) {
diff --git a/src/display/editor/annotation_editor_layer.js b/src/display/editor/annotation_editor_layer.js
index 16a118735210f..11c982fbf6007 100644
--- a/src/display/editor/annotation_editor_layer.js
+++ b/src/display/editor/annotation_editor_layer.js
@@ -416,8 +416,7 @@ class AnnotationEditorLayer {
       }
 
       // Show the annotations that were hidden in enable().
-      const editables = annotationLayer.getEditableAnnotations();
-      for (const editable of editables) {
+      for (const editable of annotationLayer.getEditableAnnotations()) {
         const { id } = editable.data;
         if (this.#uiManager.isDeletedAnnotationElement(id)) {
           editable.updateEdited({ deleted: true });

From dbb6ffb8d5b390ec816fa9b6d262df6db1ff18ab Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Mon, 9 Mar 2026 16:18:48 +0100
Subject: [PATCH 2/2] Change the `Font.prototype.glyphCacheValues` method to
 return an iterator

This method is only used with loops, and it should be a tiny bit more efficient to use an iterator directly rather than first iterating through the underlying data to create a temporary `Array` that we finally iterate through at the call-site.

*Please note:* As port of these changes the chars/glyph caches, on the `Font` instances, are changed to use `Map`s rather than Objects.
---
 src/core/fonts.js | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/core/fonts.js b/src/core/fonts.js
index 499cc263f5a7b..901a350f55253 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -969,6 +969,10 @@ function createNameTable(name, proto) {
  * decoding logics whatever type it is (assuming the font type is supported).
  */
 class Font {
+  #charsCache = new Map();
+
+  #glyphCache = new Map();
+
   constructor(name, file, properties, evaluatorOptions) {
     this.name = name;
     this.psName = null;
@@ -981,9 +985,6 @@ class Font {
     this.missingFile = false;
     this.cssFontInfo = properties.cssFontInfo;
 
-    this._charsCache = Object.create(null);
-    this._glyphCache = Object.create(null);
-
     let isSerifFont = !!(properties.flags & FontFlags.Serif);
     // Fallback to checking the font name, in order to improve text-selection,
     // since the /Flags-entry is often wrong (fixes issue13845.pdf).
@@ -3385,7 +3386,7 @@ class Font {
    * @private
    */
   _charToGlyph(charcode, isSpace = false) {
-    let glyph = this._glyphCache[charcode];
+    let glyph = this.#glyphCache.get(charcode);
     // All `Glyph`-properties, except `isSpace` in multi-byte strings,
     // depend indirectly on the `charcode`.
     if (glyph?.isSpace === isSpace) {
@@ -3480,12 +3481,13 @@ class Font {
       isSpace,
       isInFont
     );
-    return (this._glyphCache[charcode] = glyph);
+    this.#glyphCache.set(charcode, glyph);
+    return glyph;
   }
 
   charsToGlyphs(chars) {
     // If we translated this string before, just grab it from the cache.
-    let glyphs = this._charsCache[chars];
+    let glyphs = this.#charsCache.get(chars);
     if (glyphs) {
       return glyphs;
     }
@@ -3517,7 +3519,8 @@ class Font {
     }
 
     // Enter the translated string into the cache.
-    return (this._charsCache[chars] = glyphs);
+    this.#charsCache.set(chars, glyphs);
+    return glyphs;
   }
 
   /**
@@ -3549,7 +3552,7 @@ class Font {
   }
 
   get glyphCacheValues() {
-    return Object.values(this._glyphCache);
+    return this.#glyphCache.values();
   }
 
   /**