Optional Class Properties Not Reflected in GraphQL Schema When Using SWC Builder

[maronnjapan]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

When generating a schema from a model using @ObjectType, if swc is specified as the builder in nestjs-cli.json, the id property does not become nullable in the schema.

import { Field, ObjectType } from "@nestjs/graphql";

@ObjectType()
export class Hoge {
    @Field(() => String)
    id?: string;
}

# generated schema
type Hoge {
  id: String!
}

However, with no builder specified, the id property becomes nullable with the above definition.

Minimum reproduction code

https://github.com/maronnjapan/test-nestjs-graphql-in-swc

Steps to reproduce

1. pnpm i
2. pnpm start:dev

Expected behavior

When switching to the swc builder, we expect the generated schema to remain the same as the default one.
Even if it changes, we would like to understand why the behavior differs when switching to the swc builder.

Package

• Other (see below)

Other package

@nestjs/graphql

NestJS version

10.4.15

Packages versions

{
  "scripts": {
    "build": "nest build",
    "start": "nest start",
    "start:dev": "nest start --watch",
    "start:debug": "nest start --debug --watch",
    "start:prod": "node dist/main",
  },
  "dependencies": {
    "@nestjs/common": "^10.0.0",
    "@nestjs/core": "^10.0.0",
    "@nestjs/graphql": "^12.2.2",
    "@nestjs/mercurius": "^12.2.2",
    "@nestjs/platform-express": "^10.0.0",
    "@nestjs/platform-fastify": "^10.4.15",
    "graphql": "^16.10.0",
    "reflect-metadata": "^0.2.0",
    "rxjs": "^7.8.1"
  },
  "devDependencies": {
    "@nestjs/cli": "^10.0.0",
    "@nestjs/schematics": "^10.0.0",
    "@nestjs/testing": "^10.0.0",
    "@swc/cli": "^0.5.2",
    "@swc/core": "^1.10.1",
    "@types/express": "^4.17.17",
    "@types/jest": "^29.5.2",
    "@types/node": "^20.3.1",
    "@types/supertest": "^6.0.0",
    "@typescript-eslint/eslint-plugin": "^8.0.0",
    "@typescript-eslint/parser": "^8.0.0",
    "eslint": "^8.42.0",
    "eslint-config-prettier": "^9.0.0",
    "eslint-plugin-prettier": "^5.0.0",
    "jest": "^29.5.0",
    "prettier": "^3.0.0",
    "source-map-support": "^0.5.21",
    "supertest": "^7.0.0",
    "ts-jest": "^29.1.0",
    "ts-loader": "^9.4.3",
    "ts-node": "^10.9.1",
    "tsconfig-paths": "^4.2.0",
    "typescript": "^5.1.3"
  },
}

Node.js version

20.11.1

In which operating systems have you tested?

• Linux

Other

The nest-cli.json in the sample project is as follows:

{
  "$schema": "https://json.schemastore.org/nest-cli",
  "collection": "@nestjs/schematics",
  "sourceRoot": "src",
  "compilerOptions": {
    "deleteOutDir": true,
    "builder":"swc",
    "plugins": [
      {"name": "@nestjs/graphql","options":{
        "controllerKeyOfComment": "true"
      }},
      "@nestjs/graphql/plugin"
    ]
  }
}

[kamilmysliwiec]

https://docs.nestjs.com/graphql/cli-plugin#swc-builder