Use Map.prototype.getOrInsertComputed() in the src/core/xfa/ folder

Author: Snuffleupagus

src/core/xfa/builder.js

@@ -166,12 +166,7 @@ class Builder {
   _addNamespacePrefix(prefixes) {
     for (const { prefix, value } of prefixes) {
       const namespace = this._searchNamespace(value);
-      let prefixStack = this._namespacePrefixes.get(prefix);
-      if (!prefixStack) {
-        prefixStack = [];
-        this._namespacePrefixes.set(prefix, prefixStack);
-      }
-      prefixStack.push(namespace);
+      this._namespacePrefixes.getOrInsert(prefix, []).push(namespace);
     }
   }
 

src/core/xfa/fonts.js

@@ -48,14 +48,11 @@ class FontFinder {
   addPdfFont(pdfFont) {
     const cssFontInfo = pdfFont.cssFontInfo;
     const name = cssFontInfo.fontFamily;
-    let font = this.fonts.get(name);
-    if (!font) {
-      font = Object.create(null);
-      this.fonts.set(name, font);
-      if (!this.defaultFont) {
-        this.defaultFont = font;
-      }
-    }
+    const font = this.fonts.getOrInsertComputed(name, () =>
+      Object.create(null)
+    );
+    this.defaultFont ??= font;
+
     let property = "";
     const fontWeight = parseFloat(cssFontInfo.fontWeight);
     if (parseFloat(cssFontInfo.italicAngle) !== 0) {

src/core/xfa/som.js

@@ -193,11 +193,7 @@ function searchNode(
       let children, cached;
 
       if (useCache) {
-        cached = somCache.get(node);
-        if (!cached) {
-          cached = new Map();
-          somCache.set(node, cached);
-        }
+        cached = somCache.getOrInsertComputed(node, () => new Map());
         children = cached.get(cacheName);
       }