js-types

let variable;
console.log(typeof variable); // undefined

variable = "1";
console.log(typeof variable); // string

variable = 2;
console.log(typeof variable); // number

variable = true;
console.log(typeof variable); // boolean

variable = {};
console.log(typeof variable); // object

variable = Symbol();
console.log(typeof variable); // symbol

//Some things to be aware of
console.log(typeof doesntExist); // is aldo undefined

variable = null;
console.log(typeof variable); // object, this is a javascript language bug

variable = function(){};
console.log(typeof variable); // function, while not a primite type it has it's own return type for the typeof operator

variable = [1,2,3];
console.log(typeof variable); // object, why for function and not array? Because of reasons :)