Mermaid error

A state transition needs a full arrow

Reproduced on Mermaid 11.17.2 · Updated 11 September 2026

A state transition needs a full arrow in Mermaid. The exact parser message, why it happens, and corrected source that renders.

What Mermaid says

Parse error on line 2:
...ateDiagram-v2  [*] -> Active
----------------------^
Expecting 'SPACE', 'NL', 'DESCR', '-->', 'HIDE_EMPTY', 'scale', 'COMPOSIT_STATE', 'STRUCT_STOP', 'STATE_DESCR', 'ID', 'FORK', 'JOIN', 'CHOICE', 'CONCURRENT', 'note', 'acc_title', 'acc_descr', 'acc_descr_multiline_value', 'CLICK', 'STRING', 'HREF', 'classDef', 'style', 'class', 'direction_tb', 'direction_bt', 'direction_rl', 'direction_lr', 'EDGE_STATE', 'STYLE_SEPARATOR', got 'INVALID'

Why it happens

State transitions use the same two-dash arrow as flowcharts. A single dash is not recognised.

The source that fails

stateDiagram-v2
  [*] -> Active

How to fix it

Write the transition with two dashes.

stateDiagram-v2
  [*] --> Active

The corrected source, rendered with Mermaid 11.17.2.

Next steps

Paste your own version into the Mermaid repair tool, which applies this correction and fourteen others and shows every change. The related page covers the surrounding syntax, and the error dictionary lists every message.