NestJS+GraphQLでISO8601DateTimeを使う

Apollo Routerを使う場合、一致する型は完全に揃える必要がある(コメントまで含めて)

src/iso8601-date-time.scalar.ts

import { Scalar, CustomScalar } from '@nestjs/graphql';
import { Kind, ValueNode } from 'graphql';

@Scalar('ISO8601DateTime')
export class ISO8601DateTime implements CustomScalar<string, Date> {
  description = 'An ISO 8601-encoded datetime';

  parseValue(value: string): Date {
    return new Date(value); // Value from the client input variables
  }

  serialize(value: Date): string {
    return value.toISOString(); // Value sent to the client
  }

  parseLiteral(ast: ValueNode): Date | null {
    if (ast.kind === Kind.STRING) {
      return new Date(ast.value);
    }
    return null; // Invalid hard-coded value (not client input)
  }
}

src/app.module.ts

import { Module } from '@nestjs/common';
import { GraphQLModule } from '@nestjs/graphql';
import { PostsModule } from './posts/posts.module';
import { UsersModule } from './users/users.module';
import { ISO8601DateTime } from './iso8601-date-time.scalar';

@Module({
  imports: [
    PostsModule,
    UsersModule,
    GraphQLModule.forRoot({
      autoSchemaFile: true,
      installSubscriptionHandlers: true,
    }),
  ],
  providers: [ISO8601DateTime],
})
export class AppModule {}

まぁAIが作ってくれたんですけどね