puppeteer wait for an event to fire

puppeteer-waitforevent.js

/**
 * Wait for the browser to fire an event (including custom events)
 * @param {string} eventName - Event name
 * @param {integer} seconds - number of seconds to wait.
 * @returns {Promise} resolves when event fires or timeout is reached
 */
async function waitForEvent(eventName, seconds) {

    seconds = seconds || 30;

    // use race to implement a timeout
    return Promise.race([

        // add event listener and wait for event to fire before returning
        page.evaluate(function(eventName) {
            return new Promise(function(resolve, reject) {
                document.addEventListener(eventName, function(e) {
                    resolve(); // resolves when the event fires
                });
            });
        }, eventName),

        // if the event does not fire within n seconds, exit
        page.waitFor(seconds * 1000)
    ]);
}