JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outerWrapper">
    <ul id="innerWrapper">
        <li class="child">I'm #01</li>
        <li class="child">I'm #02</li>
        <li class="child">I'm #03</li>
        <li class="child">I'm #04</li>
        <li class="child">I'm #05</li>
    </ul>
</div>

CSS

#outerWrapper {
    height: 300px;
    background-color: lightgreen;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: flex-end;
}

ul {
    padding: 0;
    margin: 0;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    flex-direction: column;
    /*height: 206px;*/
}

li {
    list-style-type: none;
    width: 100px;
    height: 100px;
    background-color: lightblue;
    border: 1px solid;
}

JavaScript

var innerWrapper = document.getElementById('innerWrapper');
var lastChild = innerWrapper.lastElementChild;
newHight = lastChild.offsetTop - innerWrapper.offsetTop + lastChild.offsetHeight;
innerWrapper.style.height = newHight + 'px';