Async Iterator to Observable

toObservable.js

function toObservable(asyncIter) {
    return new Observable(sink => {
    
        let abort = false;
        
        (async _=> {
            try {
                for async (let x of asyncIter) {
                    if (abort) return;
                    sink.next(x);
                }
            } catch (x) {
                sink.throw(x);
            }
        
            sink.return();
        })();
        
        return _=> {
            abort = true;
        };
    });
}

async function* g1() {
    await 1;
    yield 1;
    await 1;
    yield 2;
}

toObservable(g1()).forEach(x => console.log("!!" + x));