adds requireSingleFieldsInWhereUniqueInput generator setting

README.md

@@ -126,6 +126,12 @@ Disable usage of graphql `ID` type and use `Int/Float` for fields marked as `@id
 Type: `boolean`  
 Default: `false`
 
+#### `requireSingleFieldsInWhereUniqueInput`
+
+When a `Model`s `WhereUniqueInput` class has only a single field, mark that field as **required** (TypeScript) and **not nullable** (GraphQL). See [#58](https://github.com/unlight/prisma-nestjs-graphql/issues/58) for more details.  
+Type: `boolean`  
+Default: `false`
+
 #### `useInputType`
 
 Since GraphQL does not support input union type, this setting map

src/generate.ts

@@ -17,6 +17,7 @@ import { outputType } from './handlers/output-type';
 import { purgeOutput } from './handlers/purge-output';
 import { ReExport, reExport } from './handlers/re-export';
 import { registerEnum } from './handlers/register-enum';
+import { requireSingleFieldsInWhereUniqueInput } from './handlers/require-single-fields-in-whereunique-input';
 import { warning } from './handlers/warning';
 import { createConfig } from './helpers/create-config';
 import { factoryGetSourceFile } from './helpers/factory-get-source-file';
@@ -82,6 +83,8 @@ export async function generate(
     config.reExport !== ReExport.None && reExport(eventEmitter);
     config.emitSingle && emitSingle(eventEmitter);
     config.purgeOutput && purgeOutput(eventEmitter);
+    config.requireSingleFieldsInWhereUniqueInput &&
+        requireSingleFieldsInWhereUniqueInput(eventEmitter);
 
     const models = new Map<string, Model>();
     const modelNames: string[] = [];

src/handlers/require-single-fields-in-whereunique-input.ts

@@ -0,0 +1,24 @@
+import AwaitEventEmitter from 'await-event-emitter';
+
+import { EventArguments, InputType } from '../types';
+
+export function requireSingleFieldsInWhereUniqueInput(eventEmitter: AwaitEventEmitter) {
+    eventEmitter.on('BeforeInputType', beforeInputType);
+}
+
+function beforeInputType(args: EventArguments & { inputType: InputType }) {
+    const { inputType } = args;
+
+    if (!isWhereUniqueInputType(inputType.name) || inputType.fields.length !== 1) {
+        return;
+    }
+
+    for (const field of inputType.fields) {
+        field.isRequired = true;
+        field.isNullable = false;
+    }
+}
+
+function isWhereUniqueInputType(name: string) {
+    return name.endsWith('WhereUniqueInput');
+}

src/helpers/create-config.ts

@@ -110,6 +110,9 @@ export function createConfig(data: Record<string, unknown>) {
         purgeOutput: toBoolean(config.purgeOutput),
         useInputType: createUseInputType(config.useInputType as any),
         noTypeId: toBoolean(config.noTypeId),
+        requireSingleFieldsInWhereUniqueInput: toBoolean(
+            config.requireSingleFieldsInWhereUniqueInput,
+        ),
         decorate,
     };
 }