POC with response type

Author: baileympearson

src/operations/drop.ts

@@ -1,7 +1,6 @@
 import type { Document } from '../bson';
 import { CursorTimeoutContext } from '../cursor/abstract_cursor';
 import type { Db } from '../db';
-import { MONGODB_ERROR_CODES, MongoServerError } from '../error';
 import type { Server } from '../sdam/server';
 import type { ClientSession } from '../sessions';
 import { TimeoutContext } from '../timeout';

src/operations/execute_operation.ts

@@ -291,7 +291,7 @@ async function tryOperation<
 
       try {
         const result = await server.modernCommand(operation, timeoutContext);
-        return operation.handleOk(result) as TResult;
+        return operation.handleOk(result);
       } catch (error) {
         operation.handleError(error);
       }

src/operations/operation.ts

@@ -1,4 +1,4 @@
-import { type Connection, type MongoError } from '..';
+import { type Connection, type MongoDBResponse, type MongoError } from '..';
 import { type BSONSerializeOptions, type Document, resolveBSONOptions } from '../bson';
 import { type Abortable } from '../mongo_types';
 import { ReadPreference, type ReadPreferenceLike } from '../read_preference';
@@ -130,13 +130,18 @@ export abstract class AbstractOperation<TResult = any> {
   }
 }
 
-export abstract class ModernOperation<T> extends AbstractOperation<T> {
+export abstract class ModernOperation<
+  TResponse extends typeof MongoDBResponse | undefined,
+  TResult
+> extends AbstractOperation<TResult> {
+  abstract RESPONSE_TYPE: TResponse;
+
   /** this will never be used - but we must implement it to satisfy AbstractOperation's interface */
   override execute(
     _server: Server,
     _session: ClientSession | undefined,
     _timeoutContext: TimeoutContext
-  ): Promise<T> {
+  ): Promise<TResult> {
     throw new Error('cannot execute!!');
   }
 
@@ -148,9 +153,9 @@ export abstract class ModernOperation<T> extends AbstractOperation<T> {
    * Optional - if the operation performs error handling, such as wrapping or renaming the error,
    * this method can be overridden.
    */
-  handleOk(response: Document) {
-    return response;
-  }
+  abstract handleOk(
+    response: TResponse extends typeof MongoDBResponse ? InstanceType<TResponse> : Document
+  ): TResult;
 
   /**
    * Optional - if the operation performs post-processing

src/operations/search_indexes/drop.ts

@@ -2,13 +2,15 @@ import { type Connection, type MongoError } from '../..';
 import type { Document } from '../../bson';
 import type { Collection } from '../../collection';
 import { MONGODB_ERROR_CODES, MongoServerError } from '../../error';
-import type { Server, ServerCommandOptions } from '../../sdam/server';
+import type { ServerCommandOptions } from '../../sdam/server';
 import type { ClientSession } from '../../sessions';
 import { type TimeoutContext } from '../../timeout';
-import { AbstractOperation, ModernOperation } from '../operation';
+import { ModernOperation } from '../operation';
 
 /** @internal */
-export class DropSearchIndexOperation extends ModernOperation<void> {
+export class DropSearchIndexOperation extends ModernOperation<undefined, void> {
+  override RESPONSE_TYPE: undefined;
+
   private readonly collection: Collection;
   private readonly name: string;
 
@@ -36,6 +38,10 @@ export class DropSearchIndexOperation extends ModernOperation<void> {
     return command;
   }
 
+  override handleOk(_response: Document): void {
+    // do nothing
+  }
+
   override buildOptions(timeoutContext: TimeoutContext): ServerCommandOptions {
     return { session: this.session, timeoutContext };
   }

src/sdam/server.ts

@@ -7,7 +7,10 @@ import {
   type ConnectionPoolOptions
 } from '../cmap/connection_pool';
 import { PoolClearedError } from '../cmap/errors';
-import { type MongoDBResponseConstructor } from '../cmap/wire_protocol/responses';
+import {
+  type MongoDBResponse,
+  type MongoDBResponseConstructor
+} from '../cmap/wire_protocol/responses';
 import {
   APM_EVENTS,
   CLOSED,
@@ -40,7 +43,7 @@ import { type Abortable, TypedEventEmitter } from '../mongo_types';
 import type { GetMoreOptions } from '../operations/get_more';
 import { type ModernOperation } from '../operations/operation';
 import type { ClientSession } from '../sessions';
-import { Timeout, type TimeoutContext } from '../timeout';
+import { type TimeoutContext } from '../timeout';
 import { isTransactionCommand } from '../transactions';
 import {
   abortable,
@@ -278,10 +281,14 @@ export class Server extends TypedEventEmitter<ServerEvents> {
     }
   }
 
-  public async modernCommand(
-    operation: ModernOperation<any>,
+  public async modernCommand<TResponse extends typeof MongoDBResponse | undefined, TResult>(
+    operation: ModernOperation<TResponse, TResult>,
     timeoutContext: TimeoutContext
-  ): Promise<Document> {
+  ): Promise<
+    typeof operation.RESPONSE_TYPE extends typeof MongoDBResponse
+      ? InstanceType<TResponse>
+      : Document
+  > {
     if (this.s.state === STATE_CLOSING || this.s.state === STATE_CLOSED) {
       throw new MongoServerClosedError();
     }
@@ -326,9 +333,12 @@ export class Server extends TypedEventEmitter<ServerEvents> {
 
     try {
       try {
-        const res = await conn.command(ns, cmd, options);
+        const res = await conn.command(ns, cmd, options, operation.RESPONSE_TYPE);
         throwIfWriteConcernError(res);
-        return res;
+        // TODO: figure out why casting is necessary
+        return res as typeof operation.RESPONSE_TYPE extends typeof MongoDBResponse
+          ? InstanceType<TResponse>
+          : Document;
       } catch (commandError) {
         throw this.decorateCommandError(conn, cmd, options, commandError);
       }
@@ -349,7 +359,10 @@ export class Server extends TypedEventEmitter<ServerEvents> {
         try {
           const res = await conn.command(ns, cmd, options);
           throwIfWriteConcernError(res);
-          return res;
+          // TODO: figure out why casting is necessary
+          return res as typeof operation.RESPONSE_TYPE extends typeof MongoDBResponse
+            ? InstanceType<TResponse>
+            : Document;
         } catch (commandError) {
           throw this.decorateCommandError(conn, cmd, options, commandError);
         }