shared edge labels for branching paths in flowcharts

[ayuxsec]

In Mermaid flowcharts, edge labels are strictly bound to individual edges. This makes it impossible to express a common conditional transition that later branches without duplicating the label on multiple edges.

Example:

flowchart TD
    A -->|is_alive? yes| B
    A -->|is_alive? yes| C

flowchart TD
    A -->|is_alive? yes| B
    A -->|is_alive? yes| C

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This renders the same condition text twice, which becomes visually noisy and semantically redundant in larger diagrams.

Desired Behavior

It should be possible to express a single labeled transition that subsequently fans out to multiple nodes, conceptually equivalent to:

A --(is_alive? yes)--> {B, C}

This would allow the condition to be rendered once, improving readability and reducing duplication.

Current Workaround

The only supported workaround is to introduce an intermediate junction node:

flowchart TD
    A -->|is_alive? yes| _J(( ))
    _J(( )) --> B
    _J(( )) --> C

flowchart TD
    A -->|is_alive? yes| _J(( ))
    _J(( )) --> B
    _J(( )) --> C

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While functional, this has drawbacks:

• Adds artificial nodes that do not exist in the logical model
• Requires additional styling to make the junction visually neutral
• Scales poorly in complex decision-heavy diagrams

Question

Is this limitation a deliberate design decision, or would the maintainers be open to discussing a feature that enables shared edge labels for branching paths?