console.log(typeof "Hello" === "string");
console.log(typeof 123 === "number");
console.log(typeof undefined === "undefined");
console.log(typeof null === "object");
console.log(typeof [] === "object");
console.log(typeof {} === "object");
console.log(typeof function () {} === "function");
console.log([].constructor === Array);
console.log({}.constructor === Object);
console.log(Object.prototype.toString.call(null).slice(8, -1) === "Null");
function checkType(data) {
return Object.prototype.toString.call(data).slice(8, -1);
}