Object Definition and Implementation

There is a one to one relationship between GraphQL Interface, Scalar, Input, Union and their corresponding Typescript class:

AeroGraphQL define:

@Interface() to create a GraphQL interface
@Scalar() to create a GraphQL scalar
@Input() to create a GraphQL input
@Union() to create a GraphQL union

But to create a GraphQL object AeroGraphQL provide two decorators:

@ObjectDefinition
@ObjectImplementation

We recap here what are their differences and how they work together to create a full GraphQL object:

GraphQL object’s structure:

The Final GraphQL Object’s structure as exposed by the schema is
the union of each fields and each resolvers defined in every @ObjectDefinition and @ObjectImplementation class sharing the same GraphQL name

Both decorators must be provided with a configuration object. This configuration contain a name field which specify the name of the GraphQL object this class will refers to:
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@ObjectDefinition( { name: 'User' } )
export class User { ... } 

@ObjectImplementation( { name: 'User' } )
export class UserImpl { ... }

Fields and Resolvers

In GraphQL terms:

a @Field is a field without argument
a @Resolver is a field with arguments and an associated resolver function.

In AeroGraphQL @Field can only be defined in @ObjectDefinition while @Resolver can only be defined in ObjectImplementation

Intended usages

While classes annotated with @ObjectDefinition are never instanciated by AeroGraphQL, classes annotated with @ObjectImplementation are automatically instanciated by AeroGraphQL.

The reason is that ObjectImplementation are meant to be used within the dependency injection system in order to interact with Services defining the Busines logic, while ObjectDefinition are meant to be used as model for your database schema.