XMLHttpRequest: progress event

<div class="controls">
    <input class="xhr success" type="button" name="xhr" value="Click to start XHR (success)" />
    <input class="xhr error" type="button" name="xhr" value="Click to start XHR (error)" />
    <input class="xhr abort" type="button" name="xhr" value="Click to start XHR (abort)" />
</div>

<textarea readonly class="event-log"></textarea>

const xhrButtonSuccess = document.querySelector('.xhr.success');
const xhrButtonError = document.querySelector('.xhr.error');
const xhrButtonAbort = document.querySelector('.xhr.abort');
const log = document.querySelector('.event-log');

function handleEvent(e) {
    log.textContent = log.textContent + `${e.type}: ${e.loaded} bytes transferred\n`;
}

function addListeners(xhr) {
    xhr.addEventListener('loadstart', handleEvent);
    xhr.addEventListener('load', handleEvent);
    xhr.addEventListener('loadend', handleEvent);
    xhr.addEventListener('progress', handleEvent);
    xhr.addEventListener('error', handleEvent);
    xhr.addEventListener('abort', handleEvent);
}

function runXHR(url) {
    log.textContent = '';

    const xhr = new XMLHttpRequest();
    addListeners(xhr);
    xhr.open("GET", url);
    xhr.send();
    return xhr;
}

xhrButtonSuccess.addEventListener('click', () => {
    runXHR('https://raw.githubusercontent.com/mdn/content/main/files/en-us/_wikihistory.json');
});

xhrButtonError.addEventListener('click', () => {
    runXHR('http://i-dont-exist');
});

xhrButtonAbort.addEventListener('click', () => {
    runXHR('https://raw.githubusercontent.com/mdn/content/main/files/en-us/_wikihistory.json').abort();
});