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Mermaid error

Parentheses inside a node label break a flowchart

Reproduced on Mermaid 11.17.2 · Updated

Parentheses inside a node label break a flowchart in Mermaid. The exact parser message, why it happens, and corrected source that renders.

What Mermaid says

Parse error on line 2:
...owchart TD  A[Cost (USD)] --> B[Total]
----------------------^
Expecting 'SQE', 'DOUBLECIRCLEEND', 'PE', '-)', 'STADIUMEND', 'SUBROUTINEEND', 'PIPE', 'CYLINDEREND', 'DIAMOND_STOP', 'TAGEND', 'TRAPEND', 'INVTRAPEND', 'UNICODE_TEXT', 'TEXT', 'TAGSTART', got 'PS'

Why it happens

Round brackets are shape syntax in a flowchart. Inside an unquoted label, the first bracket is read as the start of a different node shape and the statement falls apart.

The source that fails

flowchart TD
  A[Cost (USD)] --> B[Total]

How to fix it

Wrap the label in double quotes. Everything between them is treated as text.

flowchart TD
  A["Cost (USD)"] --> B[Total]

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.