Lấy ngày hiện tại trong javascript

const getDay = (fillFlag=true) => {
  const day = new Date().getDate()
  const dayRe = day
  if (fillFlag) day < 10 ? `0${day}` : day
  return dayRe
}

//Ouput:
console.log(getDay());//27

Có thể bạn đã miss một số snippets code

closure javascript

using javascript callback style error handling

Spread Operator for Objects

Using the spread operator during an Object declaration will assign the properties of the referenced Object to the new Object.

Extend Object javascript

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.