We can't do this I'm afraid, see libp2p/js-libp2p#65

oh, it is even weird that this has only appeared now as an issue

🦆 all the way

I wish instanceof would just work..

We can use symbols for this

const peerIdSymbol = Symbol('PeerId')

class PeerId {
  constructor () {
    this[peerIdSymbol] = true
  }

  static isPeerId (other) {
    return other && other[peerIdSymbol]
  }
}

Saw this comment after pushed my change. Seems that Symbols won't work since they are different if different instances are created:

Making two versions (even patch) of peer-id different.

that's the point of symbols, you reuse the same symbol on all instances as you can see above in my example

You won't reuse if there is a js-peer-id 0.n.x and a 0.n+1.x.