// ==UserScript==
// @name         Example Userscript Keypress
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Run userscript on Shift keypress
// @author       dsasmblr
// @match        https://*.reddit.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=reddit.com
// @grant        none
// @run-at       document-idle
// ==/UserScript==

(function() {
    'use strict';

    window.doTheThing = () => {
        alert('I did it!');
    }

    document.querySelector('body').addEventListener("keydown", (event) => {
        if (event.key === "Shift") {
            window.doTheThing();
        }
    });
})();