Rendering or parsing a malformed graph definition freezes or crashes the browser

[reakaleek]

Description

When I use mermaid.run or mermaid.parse on a malformed graph definition, the browser freezes or crashes.

This will work:

sequenceDiagram
  participant Alice
  participant Bob
  Alice->>Bob: Hello

This will cause a freeze or crash

sequenceDiagram   participant Alice   participant Bob   Bob->>Alice: Hi Alice   Alice->>Bob: Hi Bob

Steps to reproduce

mermaid.parse('sequenceDiagram   participant Alice   participant Bob   Bob->>Alice: Hi Alice   Alice->>Bob: Hi Bob').catch(console.error)

Screenshots

Code Sample

https://stackblitz.com/edit/vitejs-vite-27qn1r?file=src%2FApp.tsx

Setup

• Mermaid version: 11.2.1
• Browser and Version: Version 1.69.168 Chromium: 128.0.6613.138 (Official Build) (arm64)

Suggested Solutions

No response

Additional Context

No response