v5: How to define the type of a client object?

[tukusejssirs]

I am using mqtt@5.1.3. I have a variable-length array of MQTT clients.

import {connect, MqttClient} from 'mqtt'

export interface MqttClients {
  [key: string]: MqttClient
}

const clients = {
  a: connect(...),
  b: connect(...),
}

// TS2339: Property `subscribe` does not exist on type `OperatorFunction<unknown, unknown>` (on `subscribe`)
clients.a.subscribe('topic')

// 
TS2352: Conversion of type `OperatorFunction<unknown, unknown>` to type `typeof MqttClient` may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to `unknown` first. (on `clients.a as typeof MqttClient`)
(clients.a as typeof MqttClient).subscribe('asdf')

// TS1005: `?` expected. (on the first `)`)
(clients.a as typeof MqttClient extends TypedEventEmitter<MqttClientEventCallbacks>).subscribe('asdf', null, (err: any) => {
  if (err) {
    this.logger.error([`[${schema}] MQTT subscribe : Error :`, err], {each: true})
  }
})

It does not matter if I add as unknown, as I get these errors regardless.

I get these errors at least on subscribe(), on() and end() methods.

What is the correct way to define the client object? I’d prefer doing it as simply as typeof MqttClient, however, I’d be okay withany type definition.

Thanks in advance! 🙏

[robertsLando]

MqttClient type should be fine here, maybe the error is:

const clients: MqttClients = {
  a: connect(...),
  b: connect(...),
}

[tukusejssirs]

No, that is a problem. Actually, I only forgot to do that in this demo code, not in the actual code I use.

I get the same errors when I add the type too.

[robertsLando]

When I write the exact same code on my side typescript doesn't throw any error: