platform/graphql_schema/lib/src/field.dart
2018-08-04 21:59:31 -04:00

62 lines
2.3 KiB
Dart

part of graphql_schema.src.schema;
/// Typedef for a function that resolves the value of a [GraphQLObjectField], whether asynchronously or not.
typedef FutureOr<Value> GraphQLFieldResolver<Value, Serialized>(
Serialized serialized, Map<String, dynamic> argumentValues);
/// A field on a [GraphQLObjectType].
///
/// It can have input values and additional documentation, and explicitly declares it shape
/// within the schema.
class GraphQLObjectField<Value, Serialized> {
/// The list of input values this field accepts, if any.
final List<GraphQLFieldInput> inputs = <GraphQLFieldInput>[];
/// The name of this field in serialized input.
final String name;
/// A function used to evaluate the value of this field, with respect to an arbitrary Dart value.
final GraphQLFieldResolver<Value, Serialized> resolve;
/// The [GraphQLType] associated with values that this field's [resolve] callback returns.
final GraphQLType<Value, Serialized> type;
/// An optional description of this field; useful for tools like GraphiQL.
final String description;
/// The reason that this field, if it is deprecated, was deprecated.
final String deprecationReason;
GraphQLObjectField(this.name, this.type,
{Iterable<GraphQLFieldInput> arguments: const <GraphQLFieldInput>[],
@required this.resolve,
this.deprecationReason,
this.description}) {
assert(type != null, 'GraphQL fields must specify a `type`.');
// assert(
// resolve != null, 'GraphQL fields must specify a `resolve` callback.');
this.inputs.addAll(arguments ?? <GraphQLFieldInput>[]);
}
/// Returns `true` if this field has a [deprecationReason].
bool get isDeprecated => deprecationReason?.isNotEmpty == true;
FutureOr<Serialized> serialize(Value value) {
return type.serialize(value);
}
FutureOr<Value> deserialize(Serialized serialized,
[Map<String, dynamic> argumentValues = const <String, dynamic>{}]) {
if (resolve != null) return resolve(serialized, argumentValues);
return type.deserialize(serialized);
}
@override
bool operator ==(other) =>
other is GraphQLObjectField &&
other.name == name &&
other.deprecationReason == deprecationReason &&
other.type == type &&
other.resolve == resolve &&
const ListEquality<GraphQLFieldInput>().equals(other.inputs, inputs);
}