RequestContext always returns undefined

Describe the bug The RequestContext always returns undefined after creating.

Stack trace

To Reproduce Steps to reproduce the behavior:

1. Use beneath code as middleware:

const DatbaseContextLoader = async (_req: Request, _res, next) => {
        RequestContext.create((await Database.getConnection()).em, next);
        console.log("Req context",RequestContext.currentRequestContext());
    };

1. It always logs Req context undefined

Expected behavior Return a forked em.

Additional context Using ts-node.

https://github.com/mikro-orm/mikro-orm/blob/96d771a7799a901fa0594176d64247383ee38418/lib/utils/RequestContext.ts#L31

The active property is always undefined, even after just creating.

Versions

Dependency	Version
node	v13.7.0
typescript	v3.7.3
mikro-orm	v3.0.1
your-driver	myslql2

[jsprw]

I completely misunderstood how this works then…

However, no matter where I log it, it’s always undefined: in every handler that’s called with next as well (I placed a log in your code where it retrieved the RequestContext and there it always returns undefined as domain.active is never defined?).

Also, isn’t domain deprecated in Node? https://nodejs.org/api/domain.html

[jsprw]

I found out (after lots of headaches) that zone.js (which is used by Angular SSR) was bugging the RequestContext (also in the async_hooks update)… If more people encounter this issue with zone.js, this how to create a forked em within a zone:

In any middleware that is executed befor database calls:

const em = orm.em.fork();
Zone.current
    .fork({
      name: "mikro-orm",
      properties: {
        id: em.id,
        em,
      },
      onHandleError: (
        delegate: ZoneDelegate,
        current: Zone,
        target: Zone,
        error: any
      ): boolean => {
        console.error("Database error:", error);
        return false;
      },
    })
    .run(() => {
      next();
    });

and then you can access the em within the zone with: Zone.current.get("em")

This requires zone.js to be imported in the top most file (for me it’s server.ts):

import "zone.js/dist/zone-node";

And to stop typescript complaining that types are missing (at least in zone.js 0.11.1, see https://github.com/angular/angular/pull/38585) add this to your tsconfig.json:

"types": ["node", "zone.js/zone.js"],