Scalars¶

Base scalars¶

String

Represents textual data, represented as UTF-8 character sequences. The String type is most often used by GraphQL to represent free-form human-readable text.

Int

Represents non-fractional signed whole numeric values. Int can represent values between -(2^53 - 1) and 2^53 - 1 since represented in JSON as double-precision floating point numbers specified by IEEE 754.

Float

Represents signed double-precision fractional values as specified by IEEE 754.

Boolean

Represents true or false.

ID

Represents a unique identifier, often used to refetch an object or as key for a cache. The ID type appears in a JSON response as a String; however, it is not intended to be human-readable. When expected as an input type, any string (such as “4”) or integer (such as 4) input value will be accepted as an ID.

Graphene also provides custom scalars for Dates, Times, and JSON:

graphene.Date

Represents a Date value as specified by iso8601.

graphene.DateTime

Represents a DateTime value as specified by iso8601.

graphene.Time

Represents a Time value as specified by iso8601.

Custom scalars¶

You can create custom scalars for your schema. The following is an example for creating a DateTime scalar:

  import { GraphQLScalarType } from "graphql";

  const Date = new GraphQLScalarType({
      name: 'Date',
      description: 'Date custom scalar type',
      parseValue(value) {
          return new Date(value); // value from the client
      },
      serialize(value) {
          return value.getTime(); // value sent to the client
      },
      parseLiteral(ast) {
          if (ast.kind === Kind.INT) {
              return parseInt(ast.value, 10); // ast value is always in string format
          }
          return null;
      },
});