Sequence asynchronous computations

index.js

/**
 * Run asynchronous computations sequentially
 *
 * @param {Function} f computation
 * @returns {function(*): *}
 */
const sequence = f => entries =>
  entries.reduce(
    (promise, entry) =>
      promise.then(
        () =>
          new Promise(async (resolve, reject) => {
            try {
              const result = await f(entry);
              resolve(entry)
            } catch (err) {
              reject(err)
            }
          })
      ),
    Promise.resolve()
  );

const asyncOp = item => new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve(item.id);
  }, 250)
})

const list = [
  { id: 1 },
  { id: 2 },
  { id: 3 },
  { id: 4 }
]

const asyncOpInOrder = sequence(asyncOp);

const runIt = async () => {
  console.log('+ startup')
  try {
    await asyncOpInOrder(list);
  } catch(err) {
    console.error('++ failed because', err)
  }
  console.log('+ finished processing')
}

runIt()