Mermaid.js
Website: https://mermaid.js.org/
Example of state diagram:
flowchart TD
A[Draft] -->|action_assign| B(Assigned)
B -->|action_draft| A
B -->|action_activate| C(Active)
C -->|action_reset| B
C -->|action_disable| D(Disabled)
D -->|action_enable| C
C -->|action_cancel| E(Cancelled)
D -->|action_cancel| E
E -->|action_draft| A