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

Object.keys và Object.getOwnPropertyNames

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.

How to reverse an Array?

Reversing an array in JS is really simple with the standard array method. Like below

Async await in javascript

serialize Form

Sử dụng formdata constructor để convert form, FormData, array.from(). Kết hợp window.encodeURIComponent() để encode từng value trong form.