async function*

async-function-start.js

async function* myAsyncGenerator() {
    console.log("hi");

    await Q.delay(1000);

    var a = yield 10;

    await Q.delay(100);

    var b = yield 20;

    throw new Error('boo');

    return;
}

var thingy = myAsyncGenerator();

thingy.next('ignored') // promise for { value: 10, done: false } which fulfills after 1s
thingy.next('a')       // promise for { value: 20, done: false } which fulfills after 2s
thingy.next('b');      // promise rejected with Error<'boo'> after 2s

Sync pull: generators
Async pull: generators of promises (above)

Sync push: ???
Async push: observables