Javascript Promise 객체 활용 – Value 처리

http://proinlab.com/archives/2086

Promise.values = [];

Promise.id = 0;

Promise.exec = (promise)=> {

    let thisId = Promise.id;

    if(promise) {

        promise.then((data)=> {

            Promise.values[thisId] = data;

            resolve(data);

        });

        Promise.id++;

        return promise;

    }

    Promise.id = 0;

    return new Promise((resolve)=> resolve());

}

let A = (arg1, arg2)=> new Promise((resolve)=> {

    console.log('A Executed');

    setTimeout(()=> {

        resolve({result: arg1 + arg2});

    }, 500);

});

let B = (arg1, arg2)=> new Promise((resolve)=> {

    console.log('B Executed');

    setTimeout(()=> {

        resolve({result: arg1 - arg2});

    }, 500);

});

let C = (arg1, arg2)=> new Promise((resolve)=> {

    console.log('C Executed');

    setTimeout(()=> {

        resolve({result: arg1 * arg2});

    }, 500);

});

Promise.exec()

    .then(()=> Promise.exec(A(1, 2)))

    .then((data)=> Promise.exec(B(data.result, 4)))

    .then((data)=> Promise.exec(C(Promise.values[0].result, Promise.values[1].result)))

    .then((data)=> {

        // Promise A result

        console.log('A', Promise.values[0]);

        // Promise B result

        console.log('B', Promise.values[1]);

    // Promise C result

        console.log('C', data); // or console.log(value[2]);

    });