Enums

Enums are a special kind of type that is restricted to a particular set of values.

For example, we have a few options of ice cream available, and we want to allow user to choose only from those options.

Strawberry supports defining enums using enums from python's standard library. Here's a quick tutorial on how to create an enum type in Strawberry:

First, create a new class for the new type, which extends class Enum:

from enum import Enum

class IceCreamFlavour(Enum):

Then, list options as variables in that class:

class IceCreamFlavour(Enum):
    VANILLA = "vanilla"
    STRAWBERRY = "strawberry"
    CHOCOLATE = "chocolate"

Finally we need to register our class as a strawberry type. It's done with the strawberry.enum decorator:

@strawberry.enum
class IceCreamFlavour(Enum):
    VANILLA = "vanilla"
    STRAWBERRY = "strawberry"
    CHOCOLATE = "chocolate"

Let's see how we can use Enums in our schema.

@strawberry.type
class Query:
    @strawberry.field
    def best_flavour(self) -> IceCreamFlavour:
        return IceCreamFlavour.STRAWBERRY

Defining the enum type above would produce this schema in GraphQL:

enum IceCreamFlavour {
  VANILLA
  STRAWBERRY
  CHOCOLATE
}

Here's an example of how you'd use this newly created query:

query {
  bestFlavour
}

Here is result of executed query:

{
  "data": {
    "bestFlavour": "STRAWBERRY"
  }
}

We can also use enums when defining object types (using strawberry.type). Here is an example of an object that has a field using an Enum:

@strawberry.type
class Cone:
    flavour: IceCreamFlavour
    num_scoops: int

@strawberry.type
class Query:
    @strawberry.field
    def cone(self) -> Cone:
        return Cone(flavour=IceCreamFlavour.STRAWBERRY, num_scoops=4)

And here's an example of how you'd use this query:

query {
  cone {
    flavour
    numScoops
  }
}

Here is result of executed query:

{
  "data": {
    "cone": {
      "flavour": "STRAWBERRY",
      "numScoops": 4
    }
  }
}

You can also deprecate enum value. To do so you need more verbose syntax using strawberry.enum_value and deprecation_reason. You can mix and match string and verbose syntax.

@strawberry.enum
class IceCreamFlavour(Enum):
    VANILLA = strawberry.enum_value("vanilla")
    STRAWBERRY = strawberry.enum_value(
        "strawberry", deprecation_reason="We ran out"
    )
    CHOCOLATE = "chocolate"

Additional resources

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