Fields

You can define GraphQL fields by placing a @gqlField directly before a:

Method declaration
Method signature
Property declaration
Property signature
Parameter property
Static method
Function declaration
Arrow function declaration

tip

For defining fields on the root types Query, Mutation or Subscription, see Root Fields.

Class-based fields

When using classes or interfaces to define GraphQL types, fields can be defined using class properties or methods:

/** @gqlType */
class User {
  /**
   * A description of some field.
   * @gqlField
   */
  someField: string;

  /** @gqlField */
  myField(): string {
    return "Hello World";
  }
}

Playground

Fields can also be defined using TypeScript's parameter properties, which is a short-hand for defining a field value that is passed to the class constructor:

/** @gqlType */
class User {
  constructor(
    /** @gqlField */
    public name: string,
  ) {}
}

Playground

For more information about field resolves, see Resolver Signature.

Functional style fields

If you prefer to avoid classes, types can be defined using type literals. However, this approach does not allow you to define derived/resolver fields. To solve this, Grats also allows you to define derived fields using named, exported functions. Function resolvers:

Accept an instance of the parent type as the first argument
Have a return type that matches the field type
Are exported named functions where the function name is the desired field name

/** @gqlType */
const User = {
  /** @gqlField */
  firstName: string,
  /** @gqlField */
  lastName: string,
};

export function fullName(user: User): string {
  return `${user.firstName} ${user.lastName}`;
}

Note that Grats will use the type of the first argument to determine which type is being extended. So, as seen in the previous examples, even if you don't need access to the instance you should still define a typed first argument.

Fields

Class-based fields​

Functional style fields​

More field documentation​

Class-based fields

Functional style fields

More field documentation