feat(types): change "DocumentType" to actually use a proper "_id" type

also slightly simplifys the type
typegoose · Feb 19, 2023 · c63c5f1 · c63c5f1
1 parent 740507f
commit c63c5f1
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Showing 3 changed files with 34 additions and 10 deletions.
diff --git a/docs/guides/faq.md b/docs/guides/faq.md
@@ -70,3 +70,24 @@ class Cat {
   _id: mongoose.Types.ObjectId;
 }
 ```
+
+### Why is `_id` `unknown`?
+
+It is very likely that your class is just empty, and typescript somehow does not correctly match that and treats it like a generic object.
+
+Example:
+
+```ts
+class Dummy {}
+const DummyModel = getModelForClass(Dummy);
+const newDoc = new DummyModel()
+newDoc._id; // type: unknown
+
+class Dummy {
+  // simple dummy property for types, will complain if actually used
+  public _dummy: never;
+}
+const DummyModel = getModelForClass(Dummy);
+const newDoc = new DummyModel()
+newDoc._id; // type: mongoose.Types.ObjectId
+```
diff --git a/src/types.ts b/src/types.ts
@@ -11,10 +11,8 @@ import type { Severity, PropType } from './internal/constants';
  * const doc: DocumentType<ClassName> = await NameModel.create({});
  * ```
  */
-export type DocumentType<T, QueryHelpers = BeAnObject> = (T extends { _id: unknown }
-  ? mongoose.Document<T['_id'], QueryHelpers, T>
-  : mongoose.Document<any, QueryHelpers, T>) &
-  T &
+export type DocumentType<T, QueryHelpers = BeAnObject> = mongoose.Document<unknown, QueryHelpers, T> &
+  mongoose.Require_id<T> &
   IObjectWithTypegooseFunction;
 /**
  * Get the Type of an instance of a SubDocument with Class properties

diff --git a/test/tests/types/basicTypegoose.test-d.ts b/test/tests/types/basicTypegoose.test-d.ts
@@ -1,6 +1,6 @@
 import { expectType, expectAssignable, expectError } from 'tsd-lite';
 import * as typegoose from '../../../src/typegoose';
-import { isDocument, isRefType } from '../../../src/typegoose';
+import { isDocument, isRefType, prop } from '../../../src/typegoose';
 import { BeAnObject, IObjectWithTypegooseFunction } from '../../../src/types';
 
 // decorators return type
@@ -21,7 +21,10 @@ expectType<void>(typegoose.setGlobalOptions({}));
 expectType<void>(typegoose.setLogLevel('DEBUG'));
 
 // mongoose related function return types
-class TestClass {}
+class TestClass {
+  @prop()
+  public dummy?: string;
+}
 
 const TestClassModel = typegoose.getModelForClass(TestClass);
 
@@ -166,27 +169,29 @@ async function testDocumentType() {
   const someNewDoc = new TestClassModel();
 
   expectType<
-    typegoose.mongoose.Document<any, BeAnObject, TestClass> &
+    typegoose.mongoose.Document<unknown, BeAnObject, TestClass> &
       TestClass &
       IObjectWithTypegooseFunction & { _id: typegoose.mongoose.Types.ObjectId }
   >(someNewDoc);
 
   const someCreatedDoc = await TestClassModel.create();
 
   expectType<
-    (typegoose.mongoose.Document<any, BeAnObject, TestClass> &
+    (typegoose.mongoose.Document<unknown, BeAnObject, TestClass> &
       TestClass &
       IObjectWithTypegooseFunction & { _id: typegoose.mongoose.Types.ObjectId })[]
   >(someCreatedDoc);
 
   const someFoundDoc = await TestClassModel.findOne();
 
   expectType<
-    | (typegoose.mongoose.Document<any, BeAnObject, TestClass> &
+    | (typegoose.mongoose.Document<unknown, BeAnObject, TestClass> &
         TestClass &
         IObjectWithTypegooseFunction & { _id: typegoose.mongoose.Types.ObjectId })
     | null
   >(someFoundDoc);
+
+  expectType<typegoose.mongoose.Types.ObjectId>(someNewDoc._id);
 }
 
 testDocumentType();
@@ -205,7 +210,7 @@ async function gh732() {
   const doc = await SomeClassModel.create({ someoptionalProp: 'helloopt', somerequiredProp: 'helloreq' });
 
   expectType<
-    typegoose.mongoose.Document<any, BeAnObject, SomeClass> &
+    typegoose.mongoose.Document<unknown, BeAnObject, SomeClass> &
       SomeClass &
       IObjectWithTypegooseFunction & { _id: typegoose.mongoose.Types.ObjectId }
   >(doc);