refactor: Support async parsers [internal]

packages/mermaid/src/Diagram.ts

@@ -1,10 +1,8 @@
 import * as configApi from './config.js';
-import { log } from './logger.js';
 import { getDiagram, registerDiagram } from './diagram-api/diagramAPI.js';
 import { detectType, getDiagramLoader } from './diagram-api/detectType.js';
 import { UnknownDiagramError } from './errors.js';
 import { encodeEntities } from './utils.js';
-
 import type { DetailedError } from './utils.js';
 import type { DiagramDefinition, DiagramMetadata } from './diagram-api/types.js';
 
@@ -15,51 +13,45 @@ export type ParseErrorFunction = (err: string | DetailedError | unknown, hash?:
  * @privateRemarks This is exported as part of the public mermaidAPI.
  */
 export class Diagram {
-  type = 'graph';
-  parser: DiagramDefinition['parser'];
-  renderer: DiagramDefinition['renderer'];
-  db: DiagramDefinition['db'];
-  private init?: DiagramDefinition['init'];
-
-  private detectError?: UnknownDiagramError;
-  constructor(public text: string, public metadata: Pick<DiagramMetadata, 'title'> = {}) {
-    this.text = encodeEntities(text);
-    this.text += '\n';
-    const cnf = configApi.getConfig();
+  public static async fromText(text: string, metadata: Pick<DiagramMetadata, 'title'> = {}) {
+    const config = configApi.getConfig();
+    const type = detectType(text, config);
+    text = encodeEntities(text) + '\n';
     try {
-      this.type = detectType(text, cnf);
+      getDiagram(type);
     } catch (e) {
-      this.type = 'error';
-      this.detectError = e as UnknownDiagramError;
+      const loader = getDiagramLoader(type);
+      if (!loader) {
+        throw new UnknownDiagramError(`Diagram ${type} not found.`);
+      }
+      // Diagram not available, loading it.
+      // new diagram will try getDiagram again and if fails then it is a valid throw
+      const { id, diagram } = await loader();
+      registerDiagram(id, diagram);
     }
-    const diagram = getDiagram(this.type);
-    log.debug('Type ' + this.type);
-    // Setup diagram
-    this.db = diagram.db;
-    this.renderer = diagram.renderer;
-    this.parser = diagram.parser;
-    if (this.parser.parser) {
+    const { db, parser, renderer, init } = getDiagram(type);
+    if (parser.parser) {
       // The parser.parser.yy is only present in JISON parsers. So, we'll only set if required.
-      this.parser.parser.yy = this.db;
+      parser.parser.yy = db;
     }
-    this.init = diagram.init;
-    this.parse();
-  }
-
-  parse() {
-    if (this.detectError) {
-      throw this.detectError;
-    }
-    this.db.clear?.();
-    const config = configApi.getConfig();
-    this.init?.(config);
+    db.clear?.();
+    init?.(config);
     // This block was added for legacy compatibility. Use frontmatter instead of adding more special cases.
-    if (this.metadata.title) {
-      this.db.setDiagramTitle?.(this.metadata.title);
+    if (metadata.title) {
+      db.setDiagramTitle?.(metadata.title);
     }
-    this.parser.parse(this.text);
+    await parser.parse(text);
+    return new Diagram(type, text, db, parser, renderer);
   }
 
+  private constructor(
+    public type: string,
+    public text: string,
+    public db: DiagramDefinition['db'],
+    public parser: DiagramDefinition['parser'],
+    public renderer: DiagramDefinition['renderer']
+  ) {}
+
   async render(id: string, version: string) {
     await this.renderer.draw(this.text, id, version, this);
   }
@@ -72,34 +64,3 @@ export class Diagram {
     return this.type;
   }
 }
-
-/**
- * Parse the text asynchronously and generate a Diagram object asynchronously.
- * **Warning:** This function may be changed in the future.
- * @alpha
- * @param text - The mermaid diagram definition.
- * @param metadata - Diagram metadata, defined in YAML.
- * @returns A the Promise of a Diagram object.
- * @throws {@link UnknownDiagramError} if the diagram type can not be found.
- * @privateRemarks This is exported as part of the public mermaidAPI.
- */
-export const getDiagramFromText = async (
-  text: string,
-  metadata: Pick<DiagramMetadata, 'title'> = {}
-): Promise<Diagram> => {
-  const type = detectType(text, configApi.getConfig());
-  try {
-    // Trying to find the diagram
-    getDiagram(type);
-  } catch (error) {
-    const loader = getDiagramLoader(type);
-    if (!loader) {
-      throw new UnknownDiagramError(`Diagram ${type} not found.`);
-    }
-    // Diagram not available, loading it.
-    // new diagram will try getDiagram again and if fails then it is a valid throw
-    const { id, diagram } = await loader();
-    registerDiagram(id, diagram);
-  }
-  return new Diagram(text, metadata);
-};

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

@@ -2,12 +2,12 @@ import { detectType } from './detectType.js';
 import { getDiagram, registerDiagram } from './diagramAPI.js';
 import { addDiagrams } from './diagram-orchestration.js';
 import type { DiagramDetector } from './types.js';
-import { getDiagramFromText } from '../Diagram.js';
+import { Diagram } from '../Diagram.js';
 import { it, describe, expect, beforeAll } from 'vitest';
 
 addDiagrams();
 beforeAll(async () => {
-  await getDiagramFromText('sequenceDiagram');
+  await Diagram.fromText('sequenceDiagram');
 });
 
 describe('DiagramAPI', () => {

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

@@ -121,7 +121,7 @@ export type DrawDefinition = (
 ) => void | Promise<void>;
 
 export interface ParserDefinition {
-  parse: (text: string) => void;
+  parse: (text: string) => void | Promise<void>;
   parser?: { yy: DiagramDB };
 }
 

packages/mermaid/src/diagram.spec.ts

@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'vitest';
-import { Diagram, getDiagramFromText } from './Diagram.js';
+import { Diagram } from './Diagram.js';
 import { addDetector } from './diagram-api/detectType.js';
 import { addDiagrams } from './diagram-api/diagram-orchestration.js';
 import type { DiagramLoader } from './diagram-api/types.js';
@@ -30,10 +30,10 @@ const getDummyDiagram = (id: string, title?: string): Awaited<ReturnType<Diagram
 
 describe('diagram detection', () => {
   test('should detect inbuilt diagrams', async () => {
-    const graph = (await getDiagramFromText('graph TD; A-->B')) as Diagram;
+    const graph = (await Diagram.fromText('graph TD; A-->B')) as Diagram;
     expect(graph).toBeInstanceOf(Diagram);
     expect(graph.type).toBe('flowchart-v2');
-    const sequence = (await getDiagramFromText(
+    const sequence = (await Diagram.fromText(
       'sequenceDiagram; Alice->>+John: Hello John, how are you?'
     )) as Diagram;
     expect(sequence).toBeInstanceOf(Diagram);
@@ -46,7 +46,7 @@ describe('diagram detection', () => {
       (str) => str.startsWith('loki'),
       () => Promise.resolve(getDummyDiagram('loki'))
     );
-    const diagram = await getDiagramFromText('loki TD; A-->B');
+    const diagram = await Diagram.fromText('loki TD; A-->B');
     expect(diagram).toBeInstanceOf(Diagram);
     expect(diagram.type).toBe('loki');
   });
@@ -58,19 +58,19 @@ describe('diagram detection', () => {
       (str) => str.startsWith('flowchart-elk'),
       () => Promise.resolve(getDummyDiagram('flowchart-elk', title))
     );
-    const diagram = await getDiagramFromText('flowchart-elk TD; A-->B');
+    const diagram = await Diagram.fromText('flowchart-elk TD; A-->B');
     expect(diagram).toBeInstanceOf(Diagram);
     expect(diagram.db.getDiagramTitle?.()).toBe(title);
   });
 
   test('should throw the right error for incorrect diagram', async () => {
-    await expect(getDiagramFromText('graph TD; A-->')).rejects.toThrowErrorMatchingInlineSnapshot(`
+    await expect(Diagram.fromText('graph TD; A-->')).rejects.toThrowErrorMatchingInlineSnapshot(`
       "Parse error on line 2:
       graph TD; A-->
       --------------^
       Expecting 'AMP', 'COLON', 'PIPE', 'TESTSTR', 'DOWN', 'DEFAULT', 'NUM', 'COMMA', 'NODE_STRING', 'BRKT', 'MINUS', 'MULT', 'UNICODE_TEXT', got 'EOF'"
     `);
-    await expect(getDiagramFromText('sequenceDiagram; A-->B')).rejects
+    await expect(Diagram.fromText('sequenceDiagram; A-->B')).rejects
       .toThrowErrorMatchingInlineSnapshot(`
 "Parse error on line 1:
 ...quenceDiagram; A-->B
@@ -80,13 +80,13 @@ Expecting 'TXT', got 'NEWLINE'"
   });
 
   test('should throw the right error for unregistered diagrams', async () => {
-    await expect(getDiagramFromText('thor TD; A-->B')).rejects.toThrowErrorMatchingInlineSnapshot(
+    await expect(Diagram.fromText('thor TD; A-->B')).rejects.toThrowErrorMatchingInlineSnapshot(
       '"No diagram type detected matching given configuration for text: thor TD; A-->B"'
     );
   });
 
   test('should consider entity codes when present in diagram defination', async () => {
-    const diagram = await getDiagramFromText(`sequenceDiagram
+    const diagram = await Diagram.fromText(`sequenceDiagram
     A->>B: I #9829; you!
     B->>A: I #9829; you #infin; times more!`);
     // @ts-ignore: we need to add types for sequenceDb which will be done in separate PR

packages/mermaid/src/diagrams/info/info.spec.ts

@@ -1,31 +1,27 @@
 import { parser } from './infoParser.js';
 
 describe('info', () => {
-  it('should handle an info definition', () => {
+  it('should handle an info definition', async () => {
     const str = `info`;
-    expect(() => {
-      parser.parse(str);
-    }).not.toThrow();
+    await expect(parser.parse(str)).resolves.not.toThrow();
   });
 
-  it('should handle an info definition with showInfo', () => {
+  it('should handle an info definition with showInfo', async () => {
     const str = `info showInfo`;
-    expect(() => {
-      parser.parse(str);
-    }).not.toThrow();
+    await expect(parser.parse(str)).resolves.not.toThrow();
   });
 
-  it('should throw because of unsupported info grammar', () => {
+  it('should throw because of unsupported info grammar', async () => {
     const str = `info unsupported`;
-    expect(() => {
-      parser.parse(str);
-    }).toThrow('Parsing failed: unexpected character: ->u<- at offset: 5, skipped 11 characters.');
+    await expect(parser.parse(str)).rejects.toThrow(
+      'Parsing failed: unexpected character: ->u<- at offset: 5, skipped 11 characters.'
+    );
   });
 
-  it('should throw because of unsupported info grammar', () => {
+  it('should throw because of unsupported info grammar', async () => {
     const str = `info unsupported`;
-    expect(() => {
-      parser.parse(str);
-    }).toThrow('Parsing failed: unexpected character: ->u<- at offset: 5, skipped 11 characters.');
+    await expect(parser.parse(str)).rejects.toThrow(
+      'Parsing failed: unexpected character: ->u<- at offset: 5, skipped 11 characters.'
+    );
   });
 });

packages/mermaid/src/diagrams/info/infoParser.ts

@@ -1,12 +1,11 @@
 import type { Info } from '@mermaid-js/parser';
 import { parse } from '@mermaid-js/parser';
-
-import { log } from '../../logger.js';
 import type { ParserDefinition } from '../../diagram-api/types.js';
+import { log } from '../../logger.js';
 
 export const parser: ParserDefinition = {
-  parse: (input: string): void => {
-    const ast: Info = parse('info', input);
+  parse: async (input: string): Promise<void> => {
+    const ast: Info = await parse('info', input);
     log.debug(ast);
   },
 };