CSS动画期间无法获取textIndent

Question

setInterval(function() {
   document.getElementById('indent').innerText = document.getElementById('test').style.textIndent;
}, 1000
)

.marquee {
    width: 450px;
    margin: 0 auto;
    overflow: hidden;
    white-space: nowrap;
    box-sizing: border-box;
    animation: marquee 50s linear infinite;
}

.marquee:hover {
    animation-play-state: paused
}

/* Make it move */
@keyframes marquee {
    0%   { text-indent: 27.5em }
    100% { text-indent: -105em }
}

<div id="aa">
<p id="test" class="marquee">asdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsfasdf asdf adsf</p>
</div>
<p id="indent"></p>

如您所见，我无法获得p的textIndent，我怎么能得到呢？

或者如何检查div aa内是否有可见文本？