Javascript example of asynchronous and serial processing flow in async/await reduce function

async-serial.js

const mockAsyncProcess = (objToProcess) => {
  console.time(objToProcess.id)
  console.log(`BEGIN: ${objToProcess.id}`)
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve(`RESULT -> ${objToProcess.id}`);
      console.timeEnd(objToProcess.id)
      console.log(`END: ${objToProcess.id}`)
    }, Math.random() * 1000)
  })
}

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

;(async () => {
  console.log('begin all')

  try {
    const asyncTransform = async (objToProcess) => {
      let result;

      try {
        result = await mockAsyncProcess(objToProcess)
      } catch (err) {
        console.log(err)
      }

      return result
    };

    const sequentialResult = await seriesOfRawDataToProcess.reduce(async (stack, objToProcess) => {
      return [
        ...await stack,
        await asyncTransform(objToProcess),
      ]
    }, [])

    console.log('✅', sequentialResult)
  } catch (err) {
    console.log(err)
  }

  console.log('end all')
})()