value.bind( object, keyPath )

In the example below, a keyObservable is created that is two-way bound to the value at outer.inner.key. When keyObservable.value changes, outer.inner.key is updated, and vice versa.

import { ObservableObject, value } from "can";

const outer = new ObservableObject({
  inner: {
    key: "hello"
  }
});

const keyObservable = value.bind(outer, "inner.key");

// reading `keyObservable.value`, we get the value at `outer.inner.key`
console.log(keyObservable.value); //-> "hello"

// writing to `keyObservable.value` will change the value at `outer.inner.key`
keyObservable.value = "aloha";
console.log(outer.inner.key); //->"aloha"