diff --git a/src/core/annotation.js b/src/core/annotation.js
index 2582f79a0..4ee0ab1e3 100644
--- a/src/core/annotation.js
+++ b/src/core/annotation.js
@@ -27,7 +27,6 @@ import {
   FeatureTest,
   getModificationDate,
   IDENTITY_MATRIX,
-  isAscii,
   LINE_DESCENT_FACTOR,
   LINE_FACTOR,
   OPS,
@@ -42,6 +41,7 @@ import {
   collectActions,
   getInheritableProperty,
   getRotationMatrix,
+  isAscii,
   numberToString,
   stringToUTF16String,
 } from "./core_utils.js";
diff --git a/src/core/core_utils.js b/src/core/core_utils.js
index 6794f7768..e8be16014 100644
--- a/src/core/core_utils.js
+++ b/src/core/core_utils.js
@@ -572,6 +572,10 @@ function getNewAnnotationsMap(annotationStorage) {
   return newAnnotationsByPage.size > 0 ? newAnnotationsByPage : null;
 }
 
+function isAscii(str) {
+  return /^[\x00-\x7F]*$/.test(str);
+}
+
 function stringToUTF16HexString(str) {
   const buf = [];
   for (let i = 0, ii = str.length; i < ii; i++) {
@@ -622,6 +626,7 @@ export {
   getLookupTableFactory,
   getNewAnnotationsMap,
   getRotationMatrix,
+  isAscii,
   isWhiteSpace,
   log2,
   MissingDataException,
diff --git a/src/shared/util.js b/src/shared/util.js
index 4cf01b515..c6497750b 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -1051,10 +1051,6 @@ function escapeString(str) {
   });
 }
 
-function isAscii(str) {
-  return /^[\x00-\x7F]*$/.test(str);
-}
-
 function stringToUTF8String(str) {
   return decodeURIComponent(escape(str));
 }
@@ -1168,7 +1164,6 @@ export {
   InvalidPDFException,
   isArrayBuffer,
   isArrayEqual,
-  isAscii,
   LINE_DESCENT_FACTOR,
   LINE_FACTOR,
   MissingPDFException,
diff --git a/test/unit/core_utils_spec.js b/test/unit/core_utils_spec.js
index 6072855f9..010929d99 100644
--- a/test/unit/core_utils_spec.js
+++ b/test/unit/core_utils_spec.js
@@ -18,6 +18,7 @@ import {
   encodeToXmlString,
   escapePDFName,
   getInheritableProperty,
+  isAscii,
   isWhiteSpace,
   log2,
   parseXFAPath,
@@ -335,6 +336,16 @@ describe("core_utils", function () {
     });
   });
 
+  describe("isAscii", function () {
+    it("handles ascii/non-ascii strings", function () {
+      expect(isAscii("hello world")).toEqual(true);
+      expect(isAscii("こんにちは世界の")).toEqual(false);
+      expect(isAscii("hello world in Japanese is こんにちは世界の")).toEqual(
+        false
+      );
+    });
+  });
+
   describe("stringToUTF16String", function () {
     it("should encode a string in UTF16", function () {
       expect(stringToUTF16String("hello world")).toEqual(
diff --git a/test/unit/util_spec.js b/test/unit/util_spec.js
index 3eab37e21..ed3726fde 100644
--- a/test/unit/util_spec.js
+++ b/test/unit/util_spec.js
@@ -20,7 +20,6 @@ import {
   escapeString,
   getModificationDate,
   isArrayBuffer,
-  isAscii,
   string32,
   stringToBytes,
   stringToPDFString,
@@ -259,14 +258,4 @@ describe("util", function () {
       expect(getModificationDate(date)).toEqual("31410609020653");
     });
   });
-
-  describe("isAscii", function () {
-    it("handles ascii/non-ascii strings", function () {
-      expect(isAscii("hello world")).toEqual(true);
-      expect(isAscii("こんにちは世界の")).toEqual(false);
-      expect(isAscii("hello world in Japanese is こんにちは世界の")).toEqual(
-        false
-      );
-    });
-  });
 });