怎么实现一个类型判断函数

/**
 * 类型判断
 */
function getType(target) {
  //先处理最特殊的Null
  if (target === null) {
    return "null";
  }
  //判断是不是基础类型
  const typeOfT = typeof target;
  if (typeOfT !== "object") {
    return typeOfT;
  }
  //肯定是引用类型了
  const template = {
    "[object Object]": "object",
    "[object Array]": "array",
    // 一些包装类型
    "[object String]": "object - string",
    "[object Number]": "object - number",
    "[object Boolean]": "object - boolean",
  };
  const typeStr = Object.prototype.toString.call(target);
  return template[typeStr];
}