JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="list-items" id="1">
    <li class="3"><a href="/courses/art-design-and-photography/hnc-3d-computer-animation">3D Computer Animation</a> HNC SCQF Level     7  </li>
    <li class="A"><a href="/courses/business-and-management/hnc-accounting">Accounting</a> HNC SCQF Level     7  </li>
    <li class="A"><a href="/courses/business-and-management/hnd-accounting">Accounting</a> HND SCQF Level     8  </li>
    <li class="A"><a href="/courses/business-and-management/ncga-administration">Administration</a> NCGA SCQF Level     5  </li>
    <li class="A"><a href="/courses/business-and-management/svq-administration">Administration</a> SVQ SCQF Level     5  </li>
    <li class="A"><a href="/courses/business-and-management/hnc-administration-information">Administration &amp; Information</a> HNC SCQF Level     7  </li>
    <li class="A"><a href="/courses/business-and-management/hnd-administration-information">Administration &amp; Information</a> HND SCQF Level     8  </li>
    <li class="A"><a href="/courses/computing-and-it/advanced-ecdl-word-processing-2013">Advanced ECDL: Word Processing 2013 </a> Equivalent to SCQF Level     4  </li>
    <li class="A"><a href="/courses/business-and-management/hnd-advertising-pr">Advertising &amp; PR</a> HND SCQF Level     8  </li>
    <li class="A"><a href="/courses/care/award-alcohol-awareness">Alcohol Awareness</a> Award, Level 1     Equivalent to SCQF Level     4  </li>
    <li class="A"><a href="/courses/animal-care/introduction-animal-care">Animal Care</a> Introduction SCQF Level     4/5  </li>
    <li class="A"><a href="/courses/animal-care/nc-animal-care">Animal Care</a> NC SCQF Level     5  </li>
    <li class="A"><a href="/courses/animal-care/hnd-animal-care">Animal Care</a> HND SCQF Level     8  </li>
    <li class="A"><a href="/courses/art-design-and-photography/art-design">Art &amp; Design</a> SCQF Level     4/5  </li>
    <li class="A"><a href="/courses/art-design-and-photography/nc-art-design">Art &amp; Design</a> NC...

JavaScript

var myArray = [];
$(function(){
    
    $.each($(".list-items li"), function(index, value){
        var text = $(value).text();
        var firstLetter = text.charAt(0);
        
        if(!myArray[firstLetter]) myArray[firstLetter] = [];
        myArray[firstLetter].push(text); 
    });
    
    console.log(myArray);
});