JSFiddle - React, Tailwind, and code Playground

by dswitzer

HTML

<div class="textbox-control">
  <div class="textbox-control-header">
    Top Toolbar
  </div>
  <textarea class="textbox-form-control" oninput="this.parentNode.classList[this.value.length ? 'add' : 'remove']('textbox-control-has-content'); this.parentNode.dataset.textContent = this.value;"></textarea>
  <div class="textbox-control-footer">
    Bottom Toolbar
  </div>
</div>

CSS

* {
  box-sizing: border-box;  
}

.textbox-control {
  position: relative;
  display: grid;
  border: 1px solid #ccc;
  max-width: 800px;
}

/* for autosize textarea */
.textbox-control::after {
  /* Note the weird space! Needed to preventy jumpy behavior */
  content: attr(data-text-content) " ";

  /* This is how textarea text behaves */
  white-space: pre-wrap;

  /* Hidden from view, clicks, and screen readers */
  visibility: hidden;
}

.textbox-control:focus-within
.textbox-control-has-content {
  outline: 1px solid blue;
}

.textbox-control:focus-within .textbox-control-header,
.textbox-control:focus-within .textbox-control-footer,
.textbox-control-has-content .textbox-control-header,
.textbox-control-has-content .textbox-control-footer {
  visibility: visible;
}

.textbox-control-header,
.textbox-control-footer {
  position: absolute;
  left: 0;
  right: 0;
  background-color: rgba(204, 204, 204, 0.25);
  padding: 0.25em 1em;
  height: 1.7em;
  z-index: 2;
  visibility: hidden;
}

.textbox-control-header {
  top: 0;
}

.textbox-control-footer {
  bottom: 0;
}

.textbox-control::after,
.textbox-form-control {
  padding: 2.5em 0.5em;
  width: 100%;
  border: 0;
  z-index: 1;
  outline: 0;
  /*
  resize: vertical;
  */

  /* for autosizing */
  /* Place on top of each other */
  grid-area: 1 / 1 / 2 / 2;
  font: 1em monospace;
  line-height: 1.25em;
}

 /* for autosizing */
.textbox-form-control {
  resize: none;
  /* Firefox shows scrollbar on growth, you can hide like this. */
  overflow: hidden;  
}