Nest can't resolve dependencies

I ran into a problem with NestJS dependencies, I just started learning Nest and still don't quite understand how to build the structure correctly.

> Nest can't resolve dependencies of the ChatGateway (?). Please make sure that the argument ChatAuth at index [0] is available in the ChatGateway context.

My error in terminal

chat.module.ts
`

import { Module } from '@nestjs/common';
import { ChatAuth } from './chat.middlewares';
import { ChatGateway } from './chat.gateway';
import { AuthHelper } from '../auth/auth.helper';
import { JwtStrategy } from '../auth/auth.strategy';
@Module({
imports: [ChatGateway, ChatAuth],
controllers: [],
providers: [AuthHelper, JwtStrategy],
})
export class ChatModule {}

`

chat.gateway.ts
`

import {
SubscribeMessage,
WebSocketGateway,
OnGatewayInit,
WebSocketServer,
OnGatewayConnection,
OnGatewayDisconnect,
MessageBody,
} from '@nestjs/websockets';
import { Logger } from '@nestjs/common';
import { Socket, Server } from 'socket.io';
import { ChatAuth } from './chat.middlewares';
@WebSocketGateway(7000)
export class ChatGateway
implements OnGatewayInit, OnGatewayConnection, OnGatewayDisconnect
{
@WebSocketServer() server: Server;
private chatAuthHelper: ChatAuth;
private logger: Logger = new Logger('ChatGateway');
constructor(chatAuthHelper: ChatAuth) {
this.chatAuthHelper = chatAuthHelper;
}
@SubscribeMessage('msgToServer')
handleMessage(client: Socket, payload: string): void {
console.log(payload);
this.server.emit('msgToClient', payload);
}
@SubscribeMessage('events')
handleEvent(@MessageBody() data: string): void {
const parsed = JSON.parse(JSON.stringify(data));
parsed.msg = parsed.msg + ' 3';
this.server.emit('onMessage', {
msg: 'New message',
content: parsed.msg,
});
}
afterInit(server: Server) {
this.logger.log('Init');
}
handleDisconnect(client: Socket) {
this.logger.log(`Client disconnected: ${client.id}`);
}
handleConnection(client: Socket, ...args: any[]) {
if (client.handshake.headers.authorization) {
const guard = this.chatAuthHelper.use(
client.handshake.headers.authorization,
);
}
this.logger.log(`Client connected: ${client.id}`);
}
}

`

chat.middlewares.ts
`

import { Injectable, NestMiddleware } from '@nestjs/common';
import { AuthHelper } from '../auth/auth.helper';
@Injectable()
export class ChatAuth implements NestMiddleware {
private helper: AuthHelper;
constructor(helper: AuthHelper) {
this.helper = helper;
}
public async use(token): Promise<object> {
const currentToken = token.split(' ')[1];
const user = await this.helper.validate(currentToken);
console.log(JSON.stringify(user));
return user;
}
}

`

app.module.ts
`

import { Module } from '@nestjs/common';
import * as path from 'path';
import { ConfigModule } from '@nestjs/config';
import { TypeOrmModule } from '@nestjs/typeorm';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { getEnvPath } from './common/helper/env.helper';
import { TypeOrmConfigService } from './shared/typeorm/typeorm.service';
import { ApiModule } from './api/api.module';
import { ChatModule } from './api/chat/chat.module';
const getPathConfig: string = path.join(__dirname, '..', 'env');
const envFilePath: string = getEnvPath(getPathConfig);
@Module({
imports: [
ConfigModule.forRoot({ envFilePath, isGlobal: true }),
TypeOrmModule.forRootAsync({ useClass: TypeOrmConfigService }),
ApiModule,
ChatModule,
],
controllers: [AppController],
providers: [AppService],
})
export class AppModule {}

`

Swapped ChatAuth / ChatModule imports

come on, read the docs

• ChatAuth is not a module, then there's no reason it to be listed in the imports array.
• the page https://docs.nestjs.com/websockets/gateways shows that the gateway should be in the providers array. Again, ChatGateway is not a module, then why did you put that into imports array? the docs are pretty clear on what is the role of each option of @Module({}).