fix(NODE-3430): watch method types on MongoClient and Db

src/collection.ts

@@ -1398,9 +1398,6 @@ export class Collection<TSchema extends Document = Document> {
     pipeline: Document[] = [],
     options: ChangeStreamOptions = {}
   ): ChangeStream<TLocal> {
-    pipeline = pipeline ?? [];
-    options = options ?? {};
-
     // Allow optionally not specifying a pipeline
     if (!Array.isArray(pipeline)) {
       options = pipeline;

src/db.ts

@@ -714,15 +714,10 @@ export class Db {
    * @param pipeline - An array of {@link https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/|aggregation pipeline stages} through which to pass change stream documents. This allows for filtering (using $match) and manipulating the change stream documents.
    * @param options - Optional settings for the command
    */
-  watch<TSchema = Document>(): ChangeStream<TSchema>;
-  watch<TSchema = Document>(pipeline?: Document[]): ChangeStream<TSchema>;
   watch<TSchema = Document>(
-    pipeline?: Document[],
-    options?: ChangeStreamOptions
+    pipeline: Document[] = [],
+    options: ChangeStreamOptions = {}
   ): ChangeStream<TSchema> {
-    pipeline = pipeline ?? [];
-    options = options ?? {};
-
     // Allow optionally not specifying a pipeline
     if (!Array.isArray(pipeline)) {
       options = pipeline;

src/mongo_client.ts

@@ -596,15 +596,10 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
    * @param pipeline - An array of {@link https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/|aggregation pipeline stages} through which to pass change stream documents. This allows for filtering (using $match) and manipulating the change stream documents.
    * @param options - Optional settings for the command
    */
-  watch<TSchema = Document>(): ChangeStream<TSchema>;
-  watch<TSchema = Document>(pipeline?: Document[]): ChangeStream<TSchema>;
   watch<TSchema = Document>(
     pipeline: Document[] = [],
     options: ChangeStreamOptions = {}
   ): ChangeStream<TSchema> {
-    pipeline = pipeline ?? [];
-    options = options ?? {};
-
     // Allow optionally not specifying a pipeline
     if (!Array.isArray(pipeline)) {
       options = pipeline;