fix: Remove comment line completely

packages/mermaid/src/diagram-api/comments.spec.ts

@@ -14,11 +14,8 @@ graph TD
 %% This is a comment
 `;
     expect(cleanupComments(text)).toMatchInlineSnapshot(`
-      "
+      "graph TD
-
-      graph TD
       	A-->B
-
       "
     `);
   });
@@ -38,16 +35,13 @@ graph TD
 %% This is a comment
 `;
     expect(cleanupComments(text)).toMatchInlineSnapshot(`
-      "
+      "%%{init: {'theme': 'forest'}}%%
-
-      %%{init: {'theme': 'forest'}}%%
       %%{ init: {'theme': 'space before init'}}%%
       %%{init: {'theme': 'space after ending'}}%% 
       graph TD
       	A-->B
 
       	B-->C
-
       "
     `);
   });
@@ -61,11 +55,39 @@ graph TD
 	C-->D
 `;
     expect(cleanupComments(text)).toMatchInlineSnapshot(`
+      "graph TD
+	A-->B
+	C-->D
       "
-      graph TD
+    `);
-      	A-->B
+  });
 
-      	C-->D
+  it('should remove empty newlines from start', () => {
+    const text = `
+
+
+
+
+%% This is a comment
+graph TD
+	A-->B
+`;
+    expect(cleanupComments(text)).toMatchInlineSnapshot(`
+      "graph TD
+      	A-->B
+      "
+    `);
+  });
+
+  it('should remove comments at end of text with no newline', () => {
+    const text = `
+graph TD
+	A-->B
+%% This is a comment`;
+
+    expect(cleanupComments(text)).toMatchInlineSnapshot(`
+      "graph TD
+	A-->B
       "
     `);
   });

packages/mermaid/src/diagram-api/comments.ts

@@ -4,5 +4,5 @@
  * @returns cleaned text
  */
 export const cleanupComments = (text: string): string => {
-  return text.trimStart().replace(/^\s*%%(?!{)[^\n]+/gm, '');
+  return text.trimStart().replace(/^\s*%%(?!{)[^\n]+\n?/gm, '');
 };