js的数据类型可分为基本数据类型和引用数据类型

基本数据类型(栈存储)：Undefined，Null，Boolean，Number、String

引用数据类型(堆存储)：对象、数组、函数

堆是先进先出，栈是先进后出

以下是js基本数据类型和引用类型的类型值示例：

let a = 10
let a2 = '10'
let a3 = null
let a4 = undefined
let a5 = true
let a6 = {id:1,value:'20'}
let a7 = [1,2,3,4,5,6]
let a8 = function(){
return '6'
}
console.log(typeof(a))  //number
console.log(typeof(a2))  //string
console.log(typeof(a3))  //object
console.log(typeof(a4))  //undefined
console.log(typeof(a5))  //boolean
console.log(typeof(a6))  //object
console.log(typeof(a7))  //object
console.log(typeof(a8))  //function