promise
pending -> fulfillled : resolve pending -> rejected : reject 콜백 지옥 function taskA(a,b,cb){ setTimeout(()=>{ const res = a + b; cb(res); },3000) } function taskB(a,cb){ setTimeout(()=>{ const res = a * 2; cb(res); },1000) } function taskC(a,cb){ setTimeout(()=>{ const res = a * -1; cb(res); },2000) } taskA(3,4,(a_res)=>{ console.log(a_res); taskB(a_res,(b_res)=>{ console.log(b_res); taskC(b_res,(..
2023. 9. 7.
