JSFiddle - React, Tailwind, and code Playground

HTML

<div class=a>
  <div class=b>
    <div class="c">
      <span>ashshdlskahdhdlshdkjhfsadjhsakjhdfsadj</span>
    </div>
  </div>
  <button>
    click
  </button>
</div>

CSS

body { width: 200px }

.a {
  border: solid 1px black;
  display: flex;
}

.b {
  flex: 1;
  max-width: 200px;
  overflow: hidden;
  max-height: 20px;
}
.c {
  overflow: auto;
}