JSFiddle - React, Tailwind, and code Playground

HTML

<form class="form-inline">
      <a class="btn btn-primary" data-toggle="collapse" href="#collapseExample" aria-expanded="false" aria-controls="collapseExample">
        Toggle
      </a>
      <span class="pull-left collapse width" id="collapseExample" aria-expanded="false">
        <input type="text" class="form-control" value="Anim pariatur cliche reprehenderit" />
      </span>
    </form>

CSS

.collapsing.width {
  height: auto;
  width: 0;
  -webkit-transition-property: width;
  transition-property: width;
  -webkit-transition-duration: 0.35s;
  transition-duration: 0.35s;
  -webkit-transition-timing-function: ease;
  transition-timing-function: ease;
}