SOURCE

function test(person) {
    person.age = 26
    person = {
        name: 'yyy',
        age: 30
    }
    return person
}
const p1 = {
    name: 'yck',
    age: 25
}
const p2 = test(p1)
console.log(p1)
console.log(p2)

// 原始值不能toString()，此处转成了String对象
console.log("111".toString())

var str = 'hello world'
str instanceof String // false
var str1 = new String('hello world')
str1 instanceof String // true
console.log(typeof str1) //object

let s1=Symbol()
let s2=Symbol()
console.log(s1===s2) // false
console.log(s1.toString()===s2.toString()) // true

console.log(Boolean([])) // true
console.log(Boolean(NaN)) // false

console.log('a'+ +'b') // +'b'为NaN


console.log(undefined==null) // true
console.log(''==' ') // false
console.log('0'=='') // false
console.log('0'=='') // true