js对象类型判断

js 几种判断对象的方式, typeof Object.toString

// 基本数据类型
str = ''
boolean = true
number = 1
symbol = Symbol()
_undefined = undefined
_null = null
// 引用类型
array = []
fun = function(){}
obj = {}

const target = {
  str,
  boolean,
  number,
  symbol,
  _undefined,
  _null,
  array,
  fun
}
_toString = Object.prototype.toString

function test (target, title, fun) {
  console.log('\n', title, '\n')
  for (const key in target) {
    console.log(key, fun(target[key]))
  }
}
test(target, 'typeof', function (a) {
  return typeof a
})

test(target, 'Object.prototype.toString', function (a) {
  return Object.prototype.toString.call(a)
})

/**
 typeof 

str string
boolean boolean
number number
symbol symbol
_undefined undefined
_null object
array object
fun function

 Object.prototype.toString 

str [object String]
boolean [object Boolean]
number [object Number]
symbol [object Symbol]
_undefined [object Undefined]
_null [object Null]
array [object Array]
fun [object Function]

结论:
typeof: 
引用类型,仅可以判断function
基本类型,可以判断除了null之外的类型

Object.prototype.toString.call()
可以判断所有
*/