JSFiddle - React, Tailwind, and code Playground

HTML

<dl>
  <dt>A</dt>
   <dd>A1</dd>
  <dt>B</dt>
   <dd>B1</dd>
   <dd>B2</dd>
</dl>
<div id="output"></div>

CSS

#output {
    padding    : 20px;
    background : grey;
}

JavaScript

var output = [],
    temp   = [];
$('dl').children().each(function () {
    if (this.tagName == 'DT') {
        if (0 in temp) {
            output.push(temp);
        }
        temp = [$(this).text()];
    } else {
        temp.push($(this).text());
    }
});
output.push(temp);
console.log(output);
$('#output').text(output.toSource());