JavaScript debugging tip: use a WeakMap to put a magic __id__ property on every object, use it in logs to uniquely identify objects.

weakMapDebugger.js

// https://twitter.com/dan_abramov/status/794655915769266178
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap

let ids = new weakMap()
let nextId = 1
Object.defineProperty(Object.prototype, '__id__', {
  get() {
    if (!ids.has(this)) {
      ids.set(this, nextId++)
    }
    return ids.get(this)
  }
})

var obj1 = {}
var obj2 = {}
console.log(obj1.__id__) // output: 1
console.log(obj2.__id__) // output: 2