JSFiddle - React, Tailwind, and code Playground

by Nikolay Petrov

HTML

<ul id="log">
    <li>List of keys:</li>
</ul>

CSS

.key-up { opacity: 0.5; }

JavaScript

var pressedKeys = [];

window.addEventListener("keydown", function(evt) {

    var li = pressedKeys[evt.key];
    if (!li) {
        pressedKeys[evt.key] = li;
    }
    console.log(pressedKeys);
    return false;
});

window.addEventListener("keyup", function(evt) {
    /* var li = pressedKeys[evt.keyCode];
    return false; */
});