wrong-decorator-signature.md

Warns when the decorator is incompatible with the decorated type
(wrong-decorator-signature)

Rule Details

This rule will prevent inconsistencies between TypeGraphQL decorators, and the types that they are decorating. By default, the following mappings of types are considered valid:

TypeScript type	Decorator type
number	Int, Float, ID
string	String, ID
boolean	Boolean
Date	Date, String

Options

type Options = {
  customTypes: {
    [key: string]: string | string[];
  };
  replaceDefaultTypes?: boolean;
};

The rule accepts a single object as options, with the following keys:

• customTypes: this object may contain a mapping between TypeScript types and custom GraphQL types. the keys in the object are TypeScript names, and the values in the object are a string or array of strings of custom GraphQL types that they may be mapped to.
• replaceDefaultTypes: By default, custom type mappings will be added to the default type mappings listed above. By setting this flag to true, the default type mappings will not be used.

Example configuration:

{
  "type-graphql/wrong-decorator-signature": [
    "error",
    {
      "customTypes": {
        "number": "BigInt"
      }
    }
  ]
}

Examples

Examples of incorrect code for this rule:

// Decorator specifies string array, decorated type is string
@Field(() => [String])
myString!: string;

// Decorator specifies non-nullable string, decorated type is nullable string
@Query(() => String)
userName(): string | null{
  return null;
}

Examples of correct code for this rule:

@Field(() => Int, { nullable: true })
myNumber!: number | null

@Query(() => Boolean)
isLoggedIn(): boolean{
  return true;
}