diff --git a/packages/mermaid/src/__mocks__/mermaidAPI.ts b/packages/mermaid/src/__mocks__/mermaidAPI.ts
index 08c5b7eea..3102095b9 100644
--- a/packages/mermaid/src/__mocks__/mermaidAPI.ts
+++ b/packages/mermaid/src/__mocks__/mermaidAPI.ts
@@ -6,7 +6,7 @@
 import * as configApi from '../config';
 import { vi } from 'vitest';
 import { addDiagrams } from '../diagram-api/diagram-orchestration';
-import Diagram from '../Diagram';
+import Diagram, { type ParseErrorFunction } from '../Diagram';
 
 // Normally, we could just do the following to get the original `parse()`
 // implementation, however, requireActual returns a promise and it's not documented how to use withing mock file.
@@ -15,8 +15,7 @@ import Diagram from '../Diagram';
  * @param text
  * @param parseError
  */
-// eslint-disable-next-line @typescript-eslint/ban-types
-function parse(text: string, parseError?: Function): boolean {
+function parse(text: string, parseError?: ParseErrorFunction): boolean {
   addDiagrams();
   const diagram = new Diagram(text, parseError);
   return diagram.parse(text, parseError);
diff --git a/packages/mermaid/src/mermaidAPI.ts b/packages/mermaid/src/mermaidAPI.ts
index 7c967e5fd..7fe5064de 100644
--- a/packages/mermaid/src/mermaidAPI.ts
+++ b/packages/mermaid/src/mermaidAPI.ts
@@ -22,7 +22,7 @@ import classDb from './diagrams/class/classDb';
 import flowDb from './diagrams/flowchart/flowDb';
 import flowRenderer from './diagrams/flowchart/flowRenderer';
 import ganttDb from './diagrams/gantt/ganttDb';
-import Diagram, { getDiagramFromText } from './Diagram';
+import Diagram, { getDiagramFromText, type ParseErrorFunction } from './Diagram';
 import errorRenderer from './diagrams/error/errorRenderer';
 import { attachFunctions } from './interactionDb';
 import { log, setLogLevel } from './logger';
@@ -37,8 +37,7 @@ import { evaluate } from './diagrams/common/common';
  * @param text
  * @param parseError
  */
-// eslint-disable-next-line @typescript-eslint/ban-types
-function parse(text: string, parseError?: Function): boolean {
+function parse(text: string, parseError?: ParseErrorFunction): boolean {
   addDiagrams();
   const diagram = new Diagram(text, parseError);
   return diagram.parse(text, parseError);