diff --git a/packages/mermaid/src/Diagram.ts b/packages/mermaid/src/Diagram.ts
index 0aa741994..533c77350 100644
--- a/packages/mermaid/src/Diagram.ts
+++ b/packages/mermaid/src/Diagram.ts
@@ -94,7 +94,7 @@ export const getDiagramFromText = async (txt: string, parseError?: Function): Pr
     }
     // Diagram not available, loading it
     const { diagram } = await loader();
-    registerDiagram(type, diagram, undefined, diagram.injectUtils);
+    registerDiagram(type, diagram, undefined);
     // new diagram will try getDiagram again and if fails then it is a valid throw
   }
   // If either of the above worked, we have the diagram
diff --git a/packages/mermaid/src/diagram-api/diagramAPI.ts b/packages/mermaid/src/diagram-api/diagramAPI.ts
index 2bc8091ec..bb05090e3 100644
--- a/packages/mermaid/src/diagram-api/diagramAPI.ts
+++ b/packages/mermaid/src/diagram-api/diagramAPI.ts
@@ -22,17 +22,16 @@ export interface Detectors {
   [key: string]: DiagramDetector;
 }
 
+/**
+ *
+ * @param id
+ * @param diagram
+ * @param detector
+ */
 export const registerDiagram = (
   id: string,
   diagram: DiagramDefinition,
-  detector?: DiagramDetector,
-  callback?: (
-    _log: any,
-    _setLogLevel: any,
-    _getConfig: any,
-    _sanitizeText: any,
-    _setupGraphViewbox: any
-  ) => void
+  detector?: DiagramDetector
 ) => {
   if (diagrams[id]) {
     throw new Error(`Diagram ${id} already registered.`);
@@ -42,8 +41,9 @@ export const registerDiagram = (
     addDetector(id, detector);
   }
   addStylesForDiagram(id, diagram.styles);
-  if (typeof callback !== 'undefined') {
-    callback(log, setLogLevel, getConfig, sanitizeText, setupGraphViewbox);
+
+  if (diagram.injectUtils) {
+    diagram.injectUtils(log, setLogLevel, getConfig, sanitizeText, setupGraphViewbox);
   }
 };