const foo = (callback) => {
  setTimeout(
    () => {
      callback("A");
    },
    Math.floor(Math.random() * 100),
  );
};
 
const bar = (callback) => {
  setTimeout(
    () => {
      callback("B");
    },
    Math.floor(Math.random() * 100),
  );
};
 
const baz = (callback) => {
  setTimeout(
    () => {
      callback("C");
    },
    Math.floor(Math.random() * 100),
  );
};
 
const result = () => {};
 
result(); // ['C', 'A', 'B']

const foo = (callback) => {
  setTimeout(
    () => {
      callback("A");
    },
    Math.floor(Math.random() * 100),
  );
};
 
const bar = (callback) => {
  setTimeout(
    () => {
      callback("B");
    },
    Math.floor(Math.random() * 100),
  );
};
 
const baz = (callback) => {
  setTimeout(
    () => {
      callback("C");
    },
    Math.floor(Math.random() * 100),
  );
};
 
const result = () =>
  Promise.all([new Promise(baz), new Promise(foo), new Promise(bar)]).then(
    console.log,
  );
 
result(); // ['C', 'A', 'B']