diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 7c125d72e99..5764c316090 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -899,6 +899,17 @@ namespace ts {
         return true;
     }
 
+    /* @internal */
+    export function startsWith(str: string, prefix: string): boolean {
+        return str.lastIndexOf(prefix, 0) === 0;
+    }
+
+    /* @internal */
+    export function endsWith(str: string, suffix: string): boolean {
+        const expectedPos = str.length - suffix.length;
+        return expectedPos >= 0 && str.indexOf(suffix, expectedPos) === expectedPos;
+    }
+
     export function fileExtensionIs(path: string, extension: string): boolean {
         return path.length > extension.length && endsWith(path, extension);
     }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index f970a94373a..7219a5bbd24 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -3113,13 +3113,4 @@ namespace ts {
     export function isParameterPropertyDeclaration(node: ParameterDeclaration): boolean {
         return node.flags & NodeFlags.ParameterPropertyModifier && node.parent.kind === SyntaxKind.Constructor && isClassLike(node.parent.parent);
     }
-
-    export function startsWith(str: string, prefix: string): boolean {
-        return str.lastIndexOf(prefix, 0) === 0;
-    }
-
-    export function endsWith(str: string, suffix: string): boolean {
-        const expectedPos = str.length - suffix.length;
-        return expectedPos >= 0 && str.indexOf(suffix, expectedPos) === expectedPos;
-    }
 }