Merge pull request #11560 from mohammad0-0ahmad-forks/#11532

Fix: Populate query return type.
Automattic · Mar 27, 2022 · c2103cb · c2103cb
2 parents 0ee823d + a955a08
commit c2103cb
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Showing 2 changed files with 34 additions and 4 deletions.
diff --git a/test/types/populate.test.ts b/test/types/populate.test.ts
@@ -170,12 +170,14 @@ function gh11503() {
   const User = model<IUser>('friends', userSchema);
 
   User.findOne({}).populate('friends').then(user => {
-    expectType<Types.ObjectId | undefined>(user?.friends[0]);
+    if (!user) return;
+    expectType<Types.ObjectId>(user?.friends[0]);
     expectError(user?.friends[0].blocked);
     expectError(user?.friends.map(friend => friend.blocked));
   });
 
   User.findOne({}).populate<{ friends: Friend[] }>('friends').then(user => {
+    if (!user) return;
     expectAssignable<Friend>(user?.friends[0]);
     expectType<boolean>(user?.friends[0].blocked);
     const firstFriendBlockedValue = user?.friends.map(friend => friend)[0];
@@ -197,4 +199,32 @@ function gh11544() {
   User.findOne({}).populate({ path: 'friends', strictPopulate: false });
   User.findOne({}).populate({ path: 'friends', strictPopulate: true });
   User.findOne({}).populate({ path: 'friends', populate: { path: 'someNestedPath', strictPopulate: false } });
+}
+
+async function _11532() {
+  interface IParent {
+    name: string;
+    child: Types.ObjectId;
+  }
+  interface IChild {
+    name: string;
+  }
+
+  const parentSchema = new Schema(
+    {
+      name: { type: String, required: true },
+      child: { type: Schema.Types.ObjectId, ref: 'Child', required: true }
+    });
+
+  const parent = model<IParent>('Parent', parentSchema);
+
+  const populateQuery = parent.findOne().populate<{ child: IChild }>('child');
+  const populateResult = await populateQuery;
+  const leanResult = await populateQuery.lean();
+
+  if (!populateResult) return;
+  expectType<string>(populateResult.child.name);
+
+  if (!leanResult) return;
+  expectType<string>(leanResult.child.name);
 }
diff --git a/types/index.d.ts b/types/index.d.ts
@@ -1471,7 +1471,7 @@ declare module 'mongoose' {
 
   type QueryWithHelpers<ResultType, DocType, THelpers = {}, RawDocType = DocType> = Query<ResultType, DocType, THelpers, RawDocType> & THelpers;
 
-  type UnpackedIntersection<T, U> = T extends (infer A)[]
+  type UnpackedIntersection<T, U> = T extends null ? null : T extends (infer A)[]
     ? (Omit<A, keyof U> & U)[]
     : keyof U extends never
       ? T
@@ -1776,8 +1776,8 @@ declare module 'mongoose' {
     polygon(path: string, ...coordinatePairs: number[][]): this;
 
     /** Specifies paths which should be populated with other documents. */
-    populate<Paths = {}>(path: string | string[], select?: string | any, model?: string | Model<any, THelpers>, match?: any): QueryWithHelpers<UnpackedIntersection<ResultType, Paths>, DocType, THelpers, RawDocType>;
-    populate<Paths = {}>(options: PopulateOptions | (PopulateOptions | string)[]): QueryWithHelpers<UnpackedIntersection<ResultType, Paths>, DocType, THelpers, RawDocType>;
+    populate<Paths = {}, TRawDocType = UnpackedIntersection<ResultType, Paths>>(path: string | string[], select?: string | any, model?: string | Model<any, THelpers>, match?: any): QueryWithHelpers<TRawDocType, DocType, THelpers, TRawDocType>;
+    populate<Paths = {}, TRawDocType = UnpackedIntersection<ResultType, Paths>>(options: PopulateOptions | (PopulateOptions | string)[]): QueryWithHelpers<TRawDocType, DocType, THelpers, TRawDocType>;
 
     /** Get/set the current projection (AKA fields). Pass `null` to remove the current projection. */
     projection(): ProjectionFields<DocType> | null;