const requestURL = "http://jsonplaceholder.typicode.com/users";

// This is classic XMLHttpRequest.

const xhr = new XMLHttpRequest();

xhr.open("GET", requestURL);

// xhr.responseType = "json"; // Use it if need JSON response.

xhr.onload = () => {

if (xhr.status >= 400) {

console.error(xhr.response);

} else {

console.log(JSON.parse(xhr.response));

}

}

xhr.onerror = () => console.error();

xhr.send();

// This is XMLHttpRequest with Promise.

function sendRequest(method, url, body = null) {

return new Promise((resolve, reject) => {

const xhr = new XMLHttpRequest();

xhr.open(method, url);

xhr.responseType = "json"; // Use it if need JSON response.

xhr.setRequestHeader("Content-Type", "application/json");

xhr.onload = () => {

if (xhr.status >= 400) {

reject(console.error(xhr.response));

} else {

resolve(console.log(xhr.response));

}

}

xhr.onerror = () => console.error();

xhr.send(JSON.stringify(body));

})

}

sendRequest("GET", requestURL)

.then(data => console.log(data))

.catch(error => console.error(error));

const someObject = {

prop1: "One",

prop2: 1

}

sendRequest("POST", requestURL, someObject)

.then(data => console.log(data))

.catch(error => console.error(error))