fix: distinct typing

Author: durran

src/collection.ts

@@ -17,6 +17,7 @@ import {
 } from './cursor/list_search_indexes_cursor';
 import type { Db } from './db';
 import { MongoAPIError, MongoInvalidArgumentError, MongoOperationTimeoutError } from './error';
+import { type ExplainCommandOptions, type ExplainVerbosityLike } from './explain';
 import type { MongoClient, PkFactory } from './mongo_client';
 import type {
   Abortable,
@@ -853,31 +854,32 @@ export class Collection<TSchema extends Document = Document> {
    */
   distinct<Key extends keyof WithId<TSchema>>(
     key: Key
-  ): Promise<Array<Flatten<WithId<TSchema>[Key]>> | Document>;
+  ): Promise<Array<Flatten<WithId<TSchema>[Key]>>>;
   distinct<Key extends keyof WithId<TSchema>>(
     key: Key,
     filter: Filter<TSchema>
-  ): Promise<Array<Flatten<WithId<TSchema>[Key]>> | Document>;
+  ): Promise<Array<Flatten<WithId<TSchema>[Key]>>>;
   distinct<Key extends keyof WithId<TSchema>>(
     key: Key,
     filter: Filter<TSchema>,
     options: DistinctOptions
-  ): Promise<Array<Flatten<WithId<TSchema>[Key]>> | Document>;
+  ): Promise<Array<Flatten<WithId<TSchema>[Key]>>>;
+  distinct<Key extends keyof WithId<TSchema>>(
+    key: Key,
+    filter: Filter<TSchema>,
+    options: DistinctOptions & { explain: ExplainVerbosityLike | ExplainCommandOptions }
+  ): Promise<Document>;
 
   // Embedded documents overload
-  distinct(key: string): Promise<any[] | Document>;
-  distinct(key: string, filter: Filter<TSchema>): Promise<any[] | Document>;
-  distinct(
-    key: string,
-    filter: Filter<TSchema>,
-    options: DistinctOptions
-  ): Promise<any[] | Document>;
+  distinct(key: string): Promise<any[]>;
+  distinct(key: string, filter: Filter<TSchema>): Promise<any[]>;
+  distinct(key: string, filter: Filter<TSchema>, options: DistinctOptions): Promise<any[]>;
 
   async distinct<Key extends keyof WithId<TSchema>>(
     key: Key,
     filter: Filter<TSchema> = {},
     options: DistinctOptions = {}
-  ): Promise<any[] | Document> {
+  ): Promise<any[]> {
     return await executeOperation(
       this.client,
       new DistinctOperation(

src/operations/distinct.ts

@@ -1,4 +1,4 @@
-import { BSONType, type Document, parseUtf8ValidationOption } from '../bson';
+import { type Document } from '../bson';
 import { type Connection } from '../cmap/connection';
 import { MongoDBResponse } from '../cmap/wire_protocol/responses';
 import type { Collection } from '../collection';
@@ -21,18 +21,12 @@ export type DistinctOptions = CommandOperationOptions & {
   hint?: Document | string;
 };
 
-class DistinctResponse extends MongoDBResponse {
-  get values() {
-    return this.get('values', BSONType.array, true);
-  }
-}
-
 /**
  * Return a list of distinct values for the given key across a collection.
  * @internal
  */
 export class DistinctOperation extends ModernizedCommandOperation<any[] | Document> {
-  override SERVER_COMMAND_RESPONSE_TYPE = DistinctResponse;
+  override SERVER_COMMAND_RESPONSE_TYPE = MongoDBResponse;
   override options: DistinctOptions;
   collection: Collection;
   /** Field of the document to find distinct values for. */
@@ -75,11 +69,7 @@ export class DistinctOperation extends ModernizedCommandOperation<any[] | Docume
     if (this.explain) {
       return response.toObject(this.bsonOptions);
     }
-    const values = response.values.toObject({
-      ...this.bsonOptions,
-      validation: parseUtf8ValidationOption(this.bsonOptions)
-    });
-    return Object.entries(values).map(([_key, val]) => val);
+    return response.toObject(this.bsonOptions).values;
   }
 }