ERR_INVALID_ARG_TYPE when setting req.session.userId

[osilkin98]

Running into this issue where the server will crash when setting req.session.userId = user.id:

TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be of type string or an instance of Buffer or Uint8Array. Received an instance of Array

I've already set my types.ts file to include the workaround for the versions of express-session ^1.17.4:

import { EntityManager, IDatabaseDriver, Connection } from "@mikro-orm/core";
import { Request, Response } from "express";
import { Session, SessionData } from "express-session";

export type MyContext = {
  em: EntityManager<any> & EntityManager<IDatabaseDriver<Connection>>;
  res: Response;
  req: Request & {
    session: Session & Partial<SessionData> & { userId?: number };
  };
  // redis: Redis;
};

How would one go about setting the data in the request session data?

Full stack trace:

internal/process/promises.js:213
        triggerUncaughtException(err, true /* fromPromise */);
        ^

TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be of type string or an instance of Buffer or Uint8Array. Received an instance of Array
    at new NodeError (internal/errors.js:322:7)
    at Socket.Writable.write (internal/streams/writable.js:285:13)
    at RedisSocket.writeCommand (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/@node-redis/client/dist/lib/client/socket.js:57:130)
    at Commander._RedisClient_tick (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/@node-redis/client/dist/lib/client/index.js:421:64)
    at Commander._RedisClient_sendCommand (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/@node-redis/client/dist/lib/client/index.js:402:82)
    at Commander.commandsExecutor (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/@node-redis/client/dist/lib/client/index.js:160:154)
    at Commander.BaseClass.<computed> [as set] (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/@node-redis/client/dist/lib/commander.js:8:29)
    at RedisStore.set (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/connect-redis/lib/connect-redis.js:65:21)
    at Session.save (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/express-session/session/session.js:72:25)
    at Session.save (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/express-session/index.js:406:15)
    at ServerResponse.end (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/express-session/index.js:335:21)
    at ServerResponse.send (/Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/express/lib/response.js:221:10)
    at /Users/oleg/Programming/tutorials/lireddit-follow/server/node_modules/apollo-server-express/dist/ApolloServer.js:89:25 {
  code: 'ERR_INVALID_ARG_TYPE'
}

[osilkin98]

Never mind; I managed to solve it.
For anyone looking for the solution, you have to set the redis client to use legacyMode in index.ts:

  const redisClient = redis.createClient({
    legacyMode: true,
  });

[allez-allez]

just ran into this issue and my solution was to switch to ioredis from redis, based on my reading there seems to be some sort of collision of types in redis v4.

additionally, ioredis uses new redis instead of redis.redisClient.

so the code that works for me is :

import redis from "ioredis"; 

const RedisStore = connectRedis(session);
const redisClient = new redis();

and the types.ts export type is unchanged