# Use Case

Actors, use cases, and the associations between them. Mermaid marks this type as beta.

## Examples

The playground samples for this type, rendered by Ondine when the documentation builds.

### Example 1

```mermaid
---
config:
  theme: default
  look: classic
  layout: dagre
---
usecase-beta
direction LR
actor Customer
actor Support
systemBoundary Storefront
  Browse("Browse catalog")
  Checkout("Checkout")
end
systemBoundary Fulfilment
  Track("Track delivery")
end
Customer --> Browse
Customer --> Checkout
Customer --> Track
Support --> Track
Checkout ..> : include Browse

```

### Example 2

```mermaid
usecase-beta
actor Normal("Normal actor")
actor Hollow("Hollow actor")@{ type: hollow }
actor Awesome("Awesome actor")@{ type: awesome }
actor Icon("Registered icon")@{ icon: "fa:user" }
actor Fallback("Missing icon fallback")@{ icon: "not-registered:user" }
Normal --> Manage
Hollow --> Manage
Awesome --> Manage
Icon --> Manage
Fallback --> Manage

```

### Example 3

```mermaid
usecase-beta
Inspect("Inspect payload")
json Payload@{
  "2": "second in source",
  "1": "first after 2",
  "enabled": true,
  "count": 3,
  "missing": null,
  "colors": ["Red", "Green"],
  "address": { "city": "Oslo" },
  "items": [{ "name": "Book" }],
  "emptyObject": {},
  "emptyArray": []
}:::data
Inspect --> Payload
classDef data stroke:#3572a5
style Payload stroke-width:2px

```

### Example 4

```mermaid
usecase-beta
actor Customer:::external
Checkout("Checkout"):::critical
systemBoundary Account
  Profile[Edit profile]
end
json Session@{ "active": true }:::data
Customer --> Checkout
Checkout --> Profile
Profile --> Session
classDef default stroke:#7f8ea3
classDef external,critical stroke-width:3px
class Customer,Checkout external,critical
class Account,Session data
style Checkout stroke:#c33,stroke-width:4px
style Account stroke:#536878

```

### Example 5

```mermaid
---
config:
  usecase:
    actorFontSize: 16
    actorFontFamily: Arial
    actorFontWeight: bold
    usecaseFontSize: 14
    usecaseFontFamily: Georgia
    usecaseFontWeight: normal
    nodeSpacing: 60
    rankSpacing: 70
    diagramPadding: 24
    colorScheme: role
    useMaxWidth: false
---
usecase-beta
direction LR
actor Customer
Browse("Browse catalog")
Customer --> Browse

```

### Example 6

```mermaid
usecase-beta
direction LR
accTitle: Online ordering use cases
accDescr {
  A customer places an order through the storefront.
  Staff review the order and inspect its data.
}
actor Customer("Customer")
actor Staff("Order staff")@{ type: hollow, business: true } <<Employee>>
systemBoundary ordering["Ordering System"]@{ type: package }:::system
  Browse("Browse products")
  Checkout("Checkout") <<Core>>:::critical
  Payment("Process payment")
  Review[Review order]
end
json OrderData@{
  "status": "pending",
  "items": [{ "name": "Book", "quantity": 1 }],
  "total": 29.95
}:::data
note for Checkout "`Validates the **cart** before payment`"
Customer starts@-- "places order" ---> Checkout
Customer --> Browse
Checkout pays@..> : include Payment
Staff --> Review
Review --> OrderData
classDef system stroke:#c8a02a,stroke-width:2px
classDef critical stroke:#c33,stroke-width:3px
classDef data stroke:#3572a5
starts@{ animation: fast }
style pays stroke:#6b46c1,stroke-width:2px

```