JavaScript Study Note

Variable name conventions

// let $function =27;// let FirstName = “Jonas”;// let PI = 3.1415;// let myFirstJob =’Programming’;// let myCurrentJob=’Teacher’;// let job1=’programmer’;// let ojb2 = ‘teacher’;
let javascriptIsFun = true;console.log(javascriptIsFun)console.log(typeof true)-booleanconsole.log(typeof javascriptIsFun)-booleanconsole.log(typeof 23)- numberconsole.log(typeof ‘Jonas’)-stringjavascriptIsFun=”Yes” console.log(typeof javascriptIsFun)let year;console.log(year)console.log(typeof year)year=1994;console.log(year)
console.log(typeof year)
console.log(typeof null)- It show as object on Console, but actualy undefiend