# Diagrams

MyST supports [Mermaid](https://mermaid.js.org) diagrams. Mermaid is a
diagramming and charting tool that renders Markdown-inspired text definitions to
create and modify diagrams dynamically. Use the ```` ```mermaid ```` language
type to create a diagram. This page gives some examples (taken from the official
site at the time of writing) but as always you can find more comprehensive
information in the official documentation.

## Flow charts

````markdown
```mermaid
graph TD;
    A-->B;
    A-->C;
    B-->D;
    C-->D;
```
````

```mermaid
graph TD;
    A-->B;
    A-->C;
    B-->D;
    C-->D;
```

## Sequence diagrams

````markdown
```mermaid
sequenceDiagram
    participant Alice
    participant Bob
    Alice->>John: Hello John, how are you?
    loop HealthCheck
        John->>John: Fight against hypochondria
    end
    Note right of John: Rational thoughts <br/>prevail!
    John-->>Alice: Great!
    John->>Bob: How about you?
    Bob-->>John: Jolly good!
```
````

```mermaid
sequenceDiagram
    participant Alice
    participant Bob
    Alice->>John: Hello John, how are you?
    loop HealthCheck
        John->>John: Fight against hypochondria
    end
    Note right of John: Rational thoughts <br/>prevail!
    John-->>Alice: Great!
    John->>Bob: How about you?
    Bob-->>John: Jolly good!
```

## Gantt charts

````markdown
```mermaid
gantt
dateFormat YYYY-MM-DD
title      Adding GANTT charts to Mermaid
excludes   weekdays 2014-01-10

section A section
Completed task            :done,    des1, 2014-01-06,2014-01-08
Active task               :active,  des2, 2014-01-09, 3d
Future task               :         des3, after des2, 5d
Future task2               :         des4, after des3, 5d
```
````

```mermaid
gantt
dateFormat YYYY-MM-DD
title      Adding GANTT charts to Mermaid
excludes   weekdays 2014-01-10

section A section
Completed task            :done,    des1, 2014-01-06,2014-01-08
Active task               :active,  des2, 2014-01-09, 3d
Future task               :         des3, after des2, 5d
Future task2               :         des4, after des3, 5d
```

## Class diagrams

````markdown
```mermaid
classDiagram
Class01 <|-- AveryLongClass : Cool
Class03 *-- Class04
Class05 o-- Class06
Class07 .. Class08
Class09 --> C2 : Where am i?
Class09 --* C3
Class09 --|> Class07
Class07 : equals()
Class07 : Object[] elementData
Class01 : size()
Class01 : int chimp
Class01 : int gorilla
Class08 <--> C2: Cool label
```
````

```mermaid
classDiagram
Class01 <|-- AveryLongClass : Cool
Class03 *-- Class04
Class05 o-- Class06
Class07 .. Class08
Class09 --> C2 : Where am i?
Class09 --* C3
Class09 --|> Class07
Class07 : equals()
Class07 : Object[] elementData
Class01 : size()
Class01 : int chimp
Class01 : int gorilla
Class08 <--> C2: Cool label
```

## Commit graphs and trees (Git graphs)

````markdown
```mermaid
    gitGraph
       commit
       commit
       branch develop
       commit
       commit
       commit
       checkout main
       commit
       commit
```
````

```mermaid
    gitGraph
       commit
       commit
       branch develop
       commit
       commit
       commit
       checkout main
       commit
       commit
```

## Entity-relationship (ER) diagrams

````markdown
```mermaid
erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ LINE-ITEM : contains
    CUSTOMER }|..|{ DELIVERY-ADDRESS : uses
```
````

```mermaid
erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ LINE-ITEM : contains
    CUSTOMER }|..|{ DELIVERY-ADDRESS : uses
```

## User journey diagrams

````markdown
```mermaid
journey
    title My working day
    section Go to work
      Make tea: 5: Me
      Go upstairs: 3: Me
      Do work: 1: Me, Cat
    section Go home
      Go downstairs: 5: Me
      Sit down: 5: Me
```
````

```mermaid
journey
    title My working day
    section Go to work
      Make tea: 5: Me
      Go upstairs: 3: Me
      Do work: 1: Me, Cat
    section Go home
      Go downstairs: 5: Me
      Sit down: 5: Me
```