const sleepSort = arr => new Promise((resolve, reject) => {
    const results = [];
    const promises = arr.map(val => new Promise((resolve, reject) => setTimeout(() => {
        results.push(val);
        resolve();
    }, val)));
    Promise.all(promises).then(() => resolve(results));
});

const elems = [123, 122, 124, 1, 500, 5, 10, 15, 900, 901, 13];
console.log(elems);
sleepSort(elems).then(sortedElems => console.log(sortedElems));