graphql-composer-decorators

# Field

# @Field

This decorator describes a field for all GraphQL types (interface, input, or type).

@ObjectType()
@InputType("InputInterface")
@InterfaceType("UserInterface")
class User {
  @Field()
  username: string;
}

Would give in SDL:

type User {
  username: string;
}

UserInterface {
  username: string;
}

input UserInput {
  username: string;
}

# @ObjectField

Works exactly like @Field except that it only sets the @ObjectType field.
Its operation is detailed on the page dedicated to ObjectType.

@ObjectType()
@InputType("InputInterface")
@InterfaceType("UserInterface")
class User {
  @ObjectField()
  username: string;
}

Would give in SDL:

type User {
  username: string;
}

UserInterface {
}

input UserInput {
}

# @InterfaceField

Works exactly like @Field except that it only sets the @InterfaceType field.
Its operation is detailed on the page dedicated to InterfaceType.

@ObjectType()
@InputType("InputInterface")
@InterfaceType("UserInterface")
class User {
  @InputField()
  username: string;
}

Would give in SDL:

type User {
}

UserInterface {
  username: string;
}

input UserInput {
}

# @InputField

Works exactly like @Field except that it only sets the @InputType field.
Its operation is detailed on the page dedicated to InputType.

@ObjectType()
@InputType("InputInterface")
@InterfaceType("UserInterface")
class User {
  @InputField()
  username: string;
}

Would give in SDL:

type User {
}

UserInterface {
}

input UserInput {
  username: string;
}

# Field parameters

Field decorators all have the same signatures:

  • @Field
  • @ObjectField
  • @InputField
  • @InterfaceField
  • @Query
  • @Mutation
  • @Subscribe (params.subscribe required)

# name

You can change the name of the GraphQL field with this parameter.

@ObjectType()
class User {
  @Field("userUsername")
  username: string;
}

Will give in SDL:

type User {
  userUsername: String
}

# type

This parameter overrides the limitations of TypeScript.
It is necessary when the type cannot be inferred as with:

  • Circular dependencies (A depends on B and B depends on A)
  • Arrays (details)
  • Generic types (details)
  • Types that differ from the inferred type (such as enum or union)
  • For a nullable or required field
@ObjectType()
class User {
  @Field(type => [String])
  username: string[];
}

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