Generator Promise Yielder

generator_promise_yielder.js

const run = function(gen, ...args){
    let iterator = gen.apply(undefined, args);
    return new Promise((resolve)=>{
        const rep = function(previousValue){
            let { done, value } = iterator[previousValue instanceof Error ? "throw" : "next"](previousValue);
            !done ? ((value instanceof Promise ? value.then((v)=>rep(v)).catch((v)=>rep(new Error(v))) : rep(value))) : resolve(value);
        }
        rep();
   })
};