js数组深拷贝

原文链接https://www.jianshu.com/p/a0077ea28dcb

// 数组拷贝
copyArr (obj) {
  var out = []
  var i = 0
  var len = obj.length
  for (; i < len; i++) {
    if (obj[i] instanceof Array) {
      out[i] = this.copyArr(obj[i])
    } else {
      out[i] = obj[i]
    }
  }
  return out
}