JS中准确判断变量类型的方法

var allVarMap = {
 // 数字
 num:123,
 // Infinity
 num1: 1 / 0,
 // NaN
 num2: null / 0,
 // 字符串
 str: 'abcdef',
 // 布尔类型
 bool: true,
 // 数组
 arr :[1, 2, 3, 4],
 // json对象
 json :{name:'wenzi', age:25},
 // 函数
 func:function(){ console.log('this is function'); },
 // 箭头函数
 func1: () => {console.log('arrow function')},
 // undefined类型
 und:undefined,
 // null类型
 nul:null,
 // date类型
 date:new Date(),
 // 正则表达式
 reg :/^[a-zA-Z]{5,20}$/,
 // 异常类型
 error:new Error()
}

var results = []
for (let i in allVarMap) {
	results.push(typeof allVarMap[i])
}
console.log(results.join())
// number,number,number,string,boolean,object,object,function,function,undefined,object,object,object,object

console.log(allVarMap.date instanceof Date) // true
console.log(allVarMap.func instanceof Function) // true

var results = []
for (let i in allVarMap) {
	results.push(Object.prototype.toString.call(allVarMap[i]))
}
console.log(results.join())
// [object Number],[object Number],[object Number],[object String],[object Boolean],[object Array],[object Object],[object Function],[object Function],[object Undefined],[object Null],[object Date],[object RegExp],[object Error]

var getVarType = function (val = 0) {
	var type = typeof val
	// object需要使用Object.prototype.toString.call判断
	if (type === 'object') {
		var typeStr = Object.prototype.toString.call(val)
		// 解析[object String]
		typeStr = typeStr.split(' ')[1]
		type = typeStr.substring(0, typeStr.length - 1)
	}
	return type
}
var results = []
for (let i in allVarMap) {
	results.push(getVarType(allVarMap[i]))
}
console.log(results.join())
// number,number,number,string,boolean,Array,Object,function,function,number,Null,Date,RegExp,Error