Hover underline animation

One of the fanciest text effects I've seen is an animated underline, where the underline appears to grow from the left side of the text when the user hovers over it. This effect can be achieved using CSS and the ::after pseudo-element. But first, let me show you what it looks like:
https://codepen.io/chalarangelo/pen/KKOpeae
So, how does one implement this effect? Like I said, we'll make use of the ::after pseudo-element to create the underline. It will need to have a width spanning the entire parent element and position: absolute to place it below the text content.
Naturally, the parent must then use display: inline-block to make the underline span just the width of the text content and position: relative to position the pseudo-element correctly.
Initially, we'll hide the pseudo-element using transform: scaleX(0) and show it on hover using transform: scaleX(1). To complete the effect, we'll add a transition to the transform property and adjust the transform-origin to make the underline appear to grow from the left side of the text.

.hover-underline-animation {
  display: inline-block;
  position: relative;
}

.hover-underline-animation::after {
  content: '';
  position: absolute;
  width: 100%;
  transform: scaleX(0);
  height: 2px;
  bottom: 0;
  left: 0;
  background-color: #0087ca;
  transform-origin: bottom right;
  transition: transform 0.25s ease-out;
}

.hover-underline-animation:hover::after {
  transform: scaleX(1);
  transform-origin: bottom left;
}

So, how does one implement this effect? Like I said, we'll make use of the ::after pseudo-element to create the underline. It will need to have a width spanning the entire parent element and position: absolute to place it below the text content.
Naturally, the parent must then use display: inline-block to make the underline span just the width of the text content and position: relative to position the pseudo-element correctly.
Initially, we'll hide the pseudo-element using transform: scaleX(0) and show it on hover using transform: scaleX(1). To complete the effect, we'll add a transition to the transform property and adjust the transform-origin to make the underline appear to grow from the left side of the text.
You can adjust the color, size, and other properties to fit your design. The most notable change you can make is the transform-origin. Reversing the values will make the underline appear to grow from the right side of the text instead. Removing the transform-origin property will make the underline grow from the center of the text.

From 30-seconds-of-code: hover-underline-animation