promise in javascript

const fs = require('fs')

const readFileWithPromise = file => {
  return new Promise((resolve, reject) => {
    fs.readFile(file, (err, data) => {
      if (err) {
        reject(err)
      } else {
        resolve(data)
      }
    })
  })
}

readFileWithPromise('/etc/passwd')
  .then(data => {
    console.log(data.toString())
    return readFileWithPromise('/etc/profile')
  })
  .then(data => {
    console.log(data.toString())
  })
  .catch(err => {
    console.log(err)
  })

Có thể bạn đã miss một số snippets code

Ajax, call jQuery POST to node.js expressjs

Rest Operator for Objects

Now we can use rest on the properties of an Object. It allows us to explicitly extract certain named variables, and assign any uncalled variables into a catchall Object.

Lấy ngày hiện tại trong javascript

flatMap()

Use flatMap() creates a new array with sub-array elements flattened by specified depth.

Object.keys và Object.getOwnPropertyNames