[JavaScript] request XMLHttpRequest (promise & async ~ await)

async function doAjaxThings() {
    // await code here
    let result = await makeRequest("GET", url);
    // code below here will only execute when await makeRequest() finished loading
    console.log(result);
}
document.addEventListener("DOMContentLoaded", function () {
    doAjaxThings();
    // create and manipulate your DOM here. doAjaxThings() will run asynchronously and not block your DOM rendering
    document.createElement("...");
    document.getElementById("...").addEventListener(...);
});

function makeRequest(method, url) {
    return new Promise(function (resolve, reject) {
        let xhr = new XMLHttpRequest();
        xhr.open(method, url);
        xhr.onload = function () {
            if (this.status >= 200 && this.status < 300) {
                resolve(xhr.response);
            } else {
                reject({
                    status: this.status,
                    statusText: xhr.statusText
                });
            }
        };
        xhr.onerror = function () {
            reject({
                status: this.status,
                statusText: xhr.statusText
            });
        };
        xhr.send();
    });
}

https://stackoverflow.com/questions/48969495/in-javascript-how-do-i-should-i-use-async-await-with-xmlhttprequest

In JavaScript how do I/should I use async/await with XMLHttpRequest?