export function clone(obj) {
  let buf;
  if (obj instanceof Array) {
    buf = []
    let i = obj.length;
    while (i--) {
      buf[i] = clone(obj[i])
    }
    return buf
  } else if (obj instanceof Object) {
    buf = {}
    for (const k in obj) {
      buf[k] = clone(obj[k])
    }
    return buf
  } else {
    return obj
  }
}