graphql-codegen で SDL から ts の型定義を自動生成する際に、graphql の enum が ts の enum として生成されてしまう。ts で enum は使いたくないので、opt out する方法を調べる。

現状

enum Role {
  ADMIN
  EDITOR
  VIEWER
}

これが、こうなる↓

export enum Role {
  Admin = 'ADMIN',
  Editor = 'EDITOR',
  Viewer = 'VIEWER'
}

理想

理想としては、こうなってほしい↓

export const ROLE  = {
  Admin: 'ADMIN',
  Editor: 'EDITOR',
  Viewer: 'VIEWER'
} as const;

export type Role = typeof ROLE[keyof typeof ROLE];

Docs を見る

https://www.the-guild.dev/graphql/codegen/plugins/typescript/typescript#config-api-reference

constEnums

type: boolean default: false

Will prefix every generated enum with const, you can read more about const enums here: > https://www.typescriptlang.org/docs/handbook/enums.html.

enum を const 付きで生成。

export const enum Role {
  Admin = 'ADMIN',
  Editor = 'EDITOR',
  Viewer = 'VIEWER'
};

enumsAsTypes

type: boolean default: false

Generates enum as TypeScript type instead of enum. Useful if you wish to generate .d.ts declaration file instead of .ts

enum の代わりに type を生成

export type Role =
  | 'ADMIN'
  | 'EDITOR'
  | 'VIEWER';

enumsAsConst

type: boolean default: false

Generates enum as TypeScript const assertions instead of enum. This can even be used to enable enum-like patterns in plain JavaScript code if you choose not to use TypeScript’s enum construct.

export const Role = {
  Admin: 'ADMIN',
  Editor: 'EDITOR',
  Viewer: 'VIEWER'
} as const;

export type Role = typeof Role[keyof typeof Role];

まとめ

enumsAsConst を利用すればOK

generates:
  path/to/file.ts:
    plugins:
      - typescript
    config:
      enumsAsConst: true