JSFiddle - React, Tailwind, and code Playground
HTML
<input id="test1" type='text' class="someClass" />
<input id="test2" type='text' class="someClass" />
<input id="test3" type='text' class="someClass" />
<input id="test4" type='text' class="someClass" />
<input id="test5" type='text' class="someClass" />
JavaScript
$(function(){
var idArray = $(".someClass").map(function(){
return this.id
}).get().join(',');
alert (idArray);
});