Ogen

An observable Async/Await. Short for (O)bservable (Gen)erator.

Write asynchronous code that looks synchronous:

const myFunc = function* (param1, param2, param3) {
  const result = yield fetchSomething(); // returns promise

  // waits for promise and uses promise result
  yield result + ' 2';
  yield param1;
  yield param2;
  yield param3;
}

Pass it into ogen() and get back an observable that lets you subscribe to all the yielded values:

const onNext = val => console.log(val);
const onError = err => console.log(err);
const onComplete = () => console.log('done.');

const asyncFunc = ogen(myFunc);

// Call the async function and pass params.
asyncFunc('a param', 'another param', 'more params!')
  .subscribe(onNext, onError, onComplete);
// future value
// future value 2
// a param
// another param
// more params!
// done.

Ogen returns a full Rx Observable instance, which means you can .map(), .filter() and .skip() to your heart’s content, among other things.

Platform Notes

Obviously, this relies on generators. Works OK with Babel, Node v4+. Does not work in any IE without polyfills.

Should work in most other modern browsers.

Written for Learn JavaScript with Eric Elliott

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