複習
example :
const Barry ={
gender: ’female’ ,
hobby:’null’
}
console.log( barry.hobby)
console.log(ellen.birthday)
>null
>undefined
if your print is not exist ~
New : check date type
Typeof
let barryage = 39
typeof barryage
> number
let age = ‘ 39 ‘
typeof age
> string
How to In String to + Var
- use ( + )
- Template Literal 使用反引號 `