ES6 rest parameters 와 spread parameter

const o = { message:'abc', age:1, gener:'Male'}
console.log(o)
{message: "abc", age: 1, gener: "Male"}

// 여기에서 ...은 rest parameter operator
const {message, ...r} = o;

console.log(message);
"abc"

console.log(r)
{age: 1, gener: "Male"}

// 여기에서...은 spread object operator

const o2 = {message, ...r}
console.log(o2)
{message: "abc", age: 1, gener: "Male"}

function requiredParam (param) {
  const requiredParamError = new Error(
  'Required parameter, "${param}" is missing.'
  )
 // preserve original stack trace
  if (typeof Error.captureStackTrace === 'function') {
    Error.captureStackTrace(
      requiredParamError,
      requiredParam
    )
  }
 throw requiredParamError
}

class Exception {
  constructor({
    message=requireParam('message'),
    ...payload
  }={}){
    Object.assign(this, {message, ...payload});
  }
}