JSFiddle - React, Tailwind, and code Playground

HTML

<select id="mySelect[]">
  <option value="1" selected="selected">Yadda</option>
  <option value="2">Yadda</option>
  <option value="3">Yadda</option>
</select>

JavaScript

console.log($('[id^=mySelect]'));
console.log($('#mySelect\\[\\]'));