show the differences between callback, promise and async-await

async.js

function longTask(int, callback) {
  if (int < 0) {
    callback(new Error('less than 0'));
  } else {
    callback(null, 'done');
  }
}

// callback
longTask(1, (err, result) => {});

// promise
const pLongTask = (int) => new Promise((resolve, reject) => {
  longTask(int, (err, result) => {
    if (err) {
      reject(err);
    } else {
      resolve(result);
    }
  })
});

pLongTask(1)
  .then((result) => {})
  .catch((err) => {});

// async-await
(async function() {
  try {
    const result = await pLongTask(1);
  } catch (error) {
    
  }
})();