Convert the PartialEvaluator.readToUnicode method to be async

src/core/evaluator.js

@@ -3765,28 +3765,30 @@ class PartialEvaluator {
     return new IdentityToUnicodeMap(properties.firstChar, properties.lastChar);
   }
 
-  readToUnicode(cmapObj) {
+  async readToUnicode(cmapObj) {
     if (!cmapObj) {
-      return Promise.resolve(null);
+      return null;
     }
     if (cmapObj instanceof Name) {
-      return CMapFactory.create({
+      const cmap = await CMapFactory.create({
         encoding: cmapObj,
         fetchBuiltInCMap: this._fetchBuiltInCMapBound,
         useCMap: null,
-      }).then(function (cmap) {
+      });
+
       if (cmap instanceof IdentityCMap) {
         return new IdentityToUnicodeMap(0, 0xffff);
       }
       return new ToUnicodeMap(cmap.getMap());
-      });
-    } else if (cmapObj instanceof BaseStream) {
-      return CMapFactory.create({
+    }
+    if (cmapObj instanceof BaseStream) {
+      try {
+        const cmap = await CMapFactory.create({
           encoding: cmapObj,
           fetchBuiltInCMap: this._fetchBuiltInCMapBound,
           useCMap: null,
-      }).then(
-        function (cmap) {
+        });
+
         if (cmap instanceof IdentityCMap) {
           return new IdentityToUnicodeMap(0, 0xffff);
         }
@@ -3815,8 +3817,7 @@ class PartialEvaluator {
           map[charCode] = String.fromCodePoint(...str);
         });
         return new ToUnicodeMap(map);
-        },
-        reason => {
+      } catch (reason) {
         if (reason instanceof AbortException) {
           return null;
         }
@@ -3826,9 +3827,8 @@ class PartialEvaluator {
         }
         throw reason;
       }
-      );
     }
-    return Promise.resolve(null);
+    return null;
   }
 
   readCidToGidMap(glyphsData, toUnicode) {