JSFiddle - React, Tailwind, and code Playground

HTML

<section id="photoBin">
    <ul>
        <li><a id="test" href="img/aaron1.jpg" title="Photo #127">127</a></li>
        <li><a href="img/aaron2.jpg" title="Photo #128">128</a></li>
        <li><a href="img/aaron3.jpg" title="Photo #129">129</a></li>
        <li><a href="img/aaron4.jpg" title="Photo #130">130</a></li>
        <li><a href="img/aaron5.jpg" title="Photo #131">131</a></li>
        <li><a href="img/aaron6.jpg" title="Photo #132">132</a></li>
    </ul>
</section>

<button>Check Size</button>

JavaScript

var slides = [];

$('li a').each(function(){

    var el = $(this);
    var imgHref= el.attr('href');
    var description = el.attr('title').split('Photo #');
    
    
    
    slides.push({
        img: imgHref,
        desc: description
    });
});

$('button').click(function() {
    alert(slides.length);
});