feat: Add diagramType to RenderResult and ParseResult #5117

packages/mermaid/src/mermaid.ts

@@ -6,7 +6,7 @@ import { dedent } from 'ts-dedent';
 import type { MermaidConfig } from './config.type.js';
 import { log } from './logger.js';
 import utils from './utils.js';
-import type { ParseOptions, RenderResult } from './mermaidAPI.js';
+import type { ParseOptions, ParseResult, RenderResult } from './mermaidAPI.js';
 import { mermaidAPI } from './mermaidAPI.js';
 import { registerLazyLoadedDiagrams, detectType } from './diagram-api/detectType.js';
 import { loadRegisteredDiagrams } from './diagram-api/loadDiagram.js';
@@ -24,6 +24,7 @@ export type {
   ParseErrorFunction,
   RenderResult,
   ParseOptions,
+  ParseResult,
   UnknownDiagramError,
 };
 
@@ -314,10 +315,10 @@ const executeQueue = async () => {
  * Parse the text and validate the syntax.
  * @param text - The mermaid diagram definition.
  * @param parseOptions - Options for parsing.
- * @returns true if the diagram is valid, false otherwise if parseOptions.suppressErrors is true.
+ * @returns - If the diagram is valid, returns an object with isValid set to true and the diagramType set to type of the diagram.
  * @throws Error if the diagram is invalid and parseOptions.suppressErrors is false.
  */
-const parse = async (text: string, parseOptions?: ParseOptions): Promise<boolean | void> => {
+const parse = async (text: string, parseOptions?: ParseOptions): Promise<ParseResult | void> => {
   return new Promise((resolve, reject) => {
     // This promise will resolve when the render call is done.
     // It will be queued first and will be executed when it is first in line

packages/mermaid/src/mermaidAPI.spec.ts

@@ -1,5 +1,5 @@
 'use strict';
-import { vi } from 'vitest';
+import { vi, it, expect, describe, beforeEach } from 'vitest';
 
 // -------------------------------------
 //  Mocks and mocking
@@ -682,17 +682,26 @@ describe('mermaidAPI', () => {
     it('returns false for invalid definition with silent option', async () => {
       await expect(
         mermaidAPI.parse('this is not a mermaid diagram definition', { suppressErrors: true })
-      ).resolves.toBe(false);
+      ).resolves.toStrictEqual({ isValid: false });
     });
     it('resolves for valid definition', async () => {
-      await expect(
-        mermaidAPI.parse('graph TD;A--x|text including URL space|B;')
-      ).resolves.toBeTruthy();
+      await expect(mermaidAPI.parse('graph TD;A--x|text including URL space|B;')).resolves
+        .toMatchInlineSnapshot(`
+        {
+          "diagramType": "flowchart-v2",
+          "isValid": true,
+        }
+      `);
     });
     it('returns true for valid definition with silent option', async () => {
       await expect(
         mermaidAPI.parse('graph TD;A--x|text including URL space|B;', { suppressErrors: true })
-      ).resolves.toBe(true);
+      ).resolves.toMatchInlineSnapshot(`
+        {
+          "diagramType": "flowchart-v2",
+          "isValid": true,
+        }
+      `);
     });
   });
 
@@ -734,7 +743,8 @@ describe('mermaidAPI', () => {
           it('should set aria-roledscription to the diagram type AND should call addSVGa11yTitleDescription', async () => {
             const a11yDiagramInfo_spy = vi.spyOn(accessibility, 'setA11yDiagramInfo');
             const a11yTitleDesc_spy = vi.spyOn(accessibility, 'addSVGa11yTitleDescription');
-            await mermaidAPI.render(id, diagramText);
+            const result = await mermaidAPI.render(id, diagramText);
+            expect(result.diagramType).toBe(expectedDiagramType);
             expect(a11yDiagramInfo_spy).toHaveBeenCalledWith(
               expect.anything(),
               expectedDiagramType

packages/mermaid/src/mermaidAPI.ts

@@ -60,6 +60,18 @@ export interface ParseOptions {
   suppressErrors?: boolean;
 }
 
+export type ParseResult =
+  | {
+      isValid: true;
+      /**
+       * The diagram type, e.g. 'flowchart', 'sequence', etc.
+       */
+      diagramType: string;
+    }
+  | {
+      isValid: false;
+    };
+
 // This makes it clear that we're working with a d3 selected element of some kind, even though it's hard to specify the exact type.
 export type D3Element = any;
 
@@ -68,6 +80,10 @@ export interface RenderResult {
    * The svg code for the rendered graph.
    */
   svg: string;
+  /**
+   * The diagram type, e.g. 'flowchart', 'sequence', etc.
+   */
+  diagramType: string;
   /**
    * Bind function to be called after the svg has been inserted into the DOM.
    * This is necessary for adding event listeners to the elements in the svg.
@@ -91,28 +107,24 @@ function processAndSetConfigs(text: string) {
  * Parse the text and validate the syntax.
  * @param text - The mermaid diagram definition.
  * @param parseOptions - Options for parsing.
- * @returns true if the diagram is valid, false otherwise if parseOptions.suppressErrors is true.
+ * @returns - If the diagram is valid, returns an object with isValid set to true and the diagramType set to type of the diagram.
  * @throws Error if the diagram is invalid and parseOptions.suppressErrors is false.
  */
 
-async function parse(text: string, parseOptions?: ParseOptions): Promise<boolean> {
+async function parse(text: string, parseOptions?: ParseOptions): Promise<ParseResult> {
   addDiagrams();
-
-  text = processAndSetConfigs(text).code;
-
   try {
-    await getDiagramFromText(text);
+    const { code } = processAndSetConfigs(text);
+    const diagram = await getDiagramFromText(code);
+    return { isValid: true, diagramType: diagram.type };
   } catch (error) {
     if (parseOptions?.suppressErrors) {
-      return false;
+      return { isValid: false };
     }
     throw error;
   }
-  return true;
 }
 
-// append !important; to each cssClass followed by a final !important, all enclosed in { }
-//
 /**
  * Create a CSS style that starts with the given class name, then the element,
  * with an enclosing block that has each of the cssClasses followed by !important;
@@ -483,6 +495,7 @@ const render = async function (
   }
 
   return {
+    diagramType,
     svg: svgCode,
     bindFunctions: diag.db.bindFunctions,
   };