obs-usingOperator.js

Rx.Observable.using(
  function resourceFactory() {
    return {
      name: 'my resource',
      unsubscribe() {
        console.log("resource disposed");
      }
    };
  },
  function obsFactory(resource) {
    return Rx.Observable.of(resource.name);
  }
)
.subscribe(
  (x) => console.log(x)
);

// output:
// my resource
// resource disposed