@hatkom/nestjs-graphql-plugin

Two complementary tools that eliminate the GraphQL schema boilerplate you would otherwise write by hand in a NestJS project:

1. TypeScript compiler plugin — auto-injects @Field() decorators on class properties typed as flavoured Prisma IDs, enums, or configured scalar aliases. Also auto-injects @ArgsType() / @InputType() on undecorated classes in *.args.ts / *.input.ts files.
2. nestjs-generate-enums CLI — scans your source tree for enums referenced in GraphQL decorators and in class properties inside *.args.ts / *.input.ts files, then generates a single file of registerEnumType(...) calls you import once from your app module.

Installation

npm install @hatkom/nestjs-graphql-plugin
# or
bun add @hatkom/nestjs-graphql-plugin

TypeScript must be installed separately (peer dependency, >=5.0.0).

1. TypeScript compiler plugin

What it does

NestJS's built-in GraphQL plugin auto-adds @Field() for primitive types but skips branded IDs, enums, and custom scalars. This plugin fills three gaps:

• Flavoured IDs — injects @Field(() => ID) for properties typed as prisma-generator-flavoured-ids (names matching ^[A-Z][A-Za-z0-9_]*Id$ imported from the configured module).
• Enums — uses the TypeScript type checker to detect both enum Foo {} and const Foo = { ... } as const enum patterns and injects @Field(() => Foo) automatically.
• Scalar aliases — optionally maps named exports from a shared module to their GraphQL scalar types (e.g. float → @Field(() => Float)).

It also auto-injects class-level decorators so none need to be written by hand:

• @ArgsType() on classes ending in Args inside *.args.ts files
• @InputType() on classes ending in Input inside *.input.ts files
• @ObjectType() on classes ending in Model inside *.model.ts files

Configuration

Register the plugin in nest-cli.json alongside @nestjs/graphql:

{
  "compilerOptions": {
    "plugins": [
      "@nestjs/graphql",
      "@hatkom/nestjs-graphql-plugin"
    ]
  }
}

With options:

{
  "compilerOptions": {
    "plugins": [
      "@nestjs/graphql",
      {
        "name": "@hatkom/nestjs-graphql-plugin",
        "options": {
          "idModulePattern": "@generated/prisma/",
          "scalarModule": "@myorg/shared",
          "scalars": {
            "float": "Float",
            "int": "Int"
          }
        }
      }
    ]
  }
}

Plugin options

| Option | Type | Default | Description | |---|---|---|---| | idModulePattern | string (regex) | @generated/prisma/ | Regex matched against the import path. Matching imports whose exported names satisfy ^[A-Z][A-Za-z0-9_]*Id$ are treated as ID types. | | scalarModule | string | (disabled) | Module from which scalar aliases are imported. When omitted, scalar handling is skipped. | | scalars | Record<string, string> | { float: "Float", int: "Int" } | Map of exported identifier → GraphQL scalar name for imports from scalarModule. | | autoArgsType | boolean | true | Auto-inject @ArgsType() on classes ending in Args inside *.args.ts files. | | autoInputType | boolean | true | Auto-inject @InputType() on classes ending in Input inside *.input.ts files. | | autoObjectType | boolean | true | Auto-inject @ObjectType() on classes ending in Model inside *.model.ts files. |

Behaviour

• For *.args.ts and *.input.ts files, auto-injects @ArgsType() / @InputType() on matching class names. For *.model.ts files, auto-injects @ObjectType() on classes ending in Model. Classes already carrying any GraphQL class decorator are left untouched.
• Inside eligible classes, injects @Field() for flavoured ID types, enums, and configured scalar aliases. Properties already carrying @Field or @HideField are skipped.
• Handles T[], Array<T>, T | null, and optional (?:) for array-ness and nullability.

Before / after

// Before — explicit decorators required on every ID, enum, and class
@ArgsType()
export class FindInvoicesArgs {
  @Field(() => ID)
  fundId: FundId

  @Field(() => InvoiceStatus)
  status: InvoiceStatus

  page?: number
}

// After — everything injected automatically at compile time
export class FindInvoicesArgs {
  fundId: FundId
  status: InvoiceStatus
  page?: number
}

2. nestjs-generate-enums CLI

What it does

NestJS requires every enum used in a GraphQL schema to be registered via registerEnumType(MyEnum, { name: 'MyEnum' }). This command scans your source tree and emits a single generated file that registers them all.

It detects enums from two sources:

• GraphQL decorators — any enum referenced via @Field(() => MyEnum), @Query, @Mutation, @Subscription, or @ResolveField.
• Args/Input class properties — enum-typed properties in *.args.ts and *.input.ts files, even without an explicit @Field() decorator (since those are injected at compile time by the plugin).

Usage

nestjs-generate-enums \
  --src apps/api/src \
  --output apps/api/src/@generated/registered-enums.ts \
  [--tsconfig apps/api/tsconfig.json] \
  [--override "src/@generated/prisma/client::SortOrder=CommitmentSortOrder"] \
  [--override "src/@generated/prisma/client::ISO3166CountryCode=CountryName"]

Options

| Option | Required | Description | |---|---|---| | --src | Yes | Source directory to scan. Paths are resolved relative to cwd. | | --output | Yes | Output file path. | | --tsconfig | No | Path to tsconfig.json. Defaults to <src>/../tsconfig.json. | | --override | No (repeatable) | Override the GraphQL name for a specific enum. Format: <module>::<EnumName>=<GraphQLName>. |

Output

The generated file imports and registers every detected enum:

// This file is generated by @hatkom/nestjs-graphql-plugin.
// Do not edit by hand. Regenerate by running nestjs-generate-enums.

import { registerEnumType } from '@nestjs/graphql'
import { CommitmentStatus, InvoiceStatus } from 'src/@generated/prisma/client'
import { SortDirection } from 'src/common/dto/sort.enum'

registerEnumType(CommitmentStatus, { name: 'CommitmentStatus' })
registerEnumType(InvoiceStatus, { name: 'InvoiceStatus' })
registerEnumType(SortDirection, { name: 'SortDirection' })

Import this file once — typically from app.module.ts and any schema generation script — so NestJS can resolve every enum referenced in your schema.

Recommended workflow

Add the command to your Prisma generation script so it stays in sync:

#!/bin/bash
# prisma-generate.sh
prisma generate
nestjs-generate-enums \
  --src src \
  --output src/@generated/registered-enums.ts

License

MIT