Async with generator on node.js

sample-generator-async.js

const generatorAsync = function(generator){  
    let gen = generator();
    let processNext = function(result){
        var val = gen.next(result);
        if (val.value && val.value.then){
            // TODO: manage error with gen.throw(...)
            val.value.then(res => processNext(res));
        } 
    };
    processNext();
};

const log = console.log.bind(console);

const promiseLog = function(msg, previousMsg = null){
    return new Promise((resolve, reject) => {
        process.nextTick(() => {
            previousMsg = previousMsg ? ` previous: ${previousMsg}`: '' ;
            log(`log: ${msg} ${previousMsg}`);
            resolve(msg);
        });
    });
};


generatorAsync(function*(){
    let old = yield promiseLog('gen1');
    old = yield promiseLog('gen2',old);
    old = yield promiseLog('gen3',old);
    old = yield promiseLog('gen4',old);
    promiseLog('gen5',old);
});