GraphQL– Optional arguments

Every field on a GraphQL object type can have zero or more arguments, for example the length field below:

	type Starship {
	id: ID!
	name: String!
	length(unit: LengthUnit = METER): Float
	}

view raw Starship.graphql hosted with ❤ by GitHub

An argument can be either required or optional. For optional arguments, you can specify a default value, like  METER in the example above.

To configure this using HotChocolate, you can use the following syntax:

	public class SharedResolvers
	{
	public double GetLength(Unit? unit, [Parent]Starship starship)
	=> ConvertToUnit(starship.Length, unit);
	private double ConvertToUnit(double length, Unit? unit)
	{
	if (unit == Unit.Foot)
	{
	return length * 3.28084d;
	}
	return length;
	}
	}

view raw SharedResolvers.cs hosted with ❤ by GitHub

	public class StarshipType
	: ObjectType<Starship>
	{
	protected override void Configure(IObjectTypeDescriptor<Starship> descriptor)
	{
	descriptor.Field(t => t.Id)
	.Type<NonNullType<IdType>>();
	descriptor.Field<SharedResolvers>(t => t.GetLength(default, default))
	.Argument("unit",a => {a.Type<LengthUnit>(); a.DefaultValue(Unit.Meter)});
	}
	}

view raw StarshipType.cs hosted with ❤ by GitHub