const flat = (arr) => {
  let newarr = []
  arr.forEach((el, i) => {
    if (el.children && Array.isArray(el.children) && el.children.length) {
      newarr = newarr.concat(flat(el.children))
    }
    newarr.push(el)
  })
  return newarr
}
export default flat