如何使用带有CSS-in-JS的React重写此按钮及其悬停效果

Question

I wanted to achieve a button with effect like this https://codepen.io/electerious/pen/rroqdL and wanted it to make it a React component.

The original example is using css variable so I thought it would be easier to implement it using CSS-in-JS, in my case I chose to use Emotion( https://emotion.sh ).

First, this is my current code

import React from "react";
import { css } from "@emotion/core";

const style = css`
  a {
    position: relative;
    display: inline-block;
    padding: 1.2em 2em;
    text-decoration: none;
    text-align: center;
    cursor: pointer;
    user-select: none;
    color: white;

    &::before {
      content: "";
      position: absolute;
      top: 0;
      left: 0;
      bottom: 0;
      right: 0;
      background: linear-gradient(135deg, #6e8efb, #a777e3);
      border-radius: 4px;
      transition: box-shadow 0.5s ease, transform 0.2s ease;
      will-change: transform;
      box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
      transform: translateY(var(--ty, 0)) rotateX(var(--rx, 0))
        rotateY(var(--ry, 0)) translateZ(var(--tz, -12px));
    }

    &:hover::before {
      box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    }

    &::after {
      position: relative;
      display: inline-block;
      content: attr(data-title);
      transition: transform 0.2s ease;
      font-weight: bold;
      letter-spacing: 0.01em;
      will-change: transform;
      transform: translateY(var(--ty, 0)) rotateX(var(--rx, 0))
        rotateY(var(--ry, 0));
    }
  }
`;

const Button = () => {
  return (
    <div css={style}>
      <a href="#" dataTitle="Awesome Button">
        Button
      </a>
    </div>
  );
};

export default Button;

However I have encountered two difficulties.

1. according the original example, it manipulates the <a/> tag directly in the js file using const aElem = document.querySelector('a') const boundingClientRect = aElem.getBoundingClientRect() . I am not sure how I can achieve this using React because it seems like I don't know how to directly access the DOM element I am about to render in React.

2. Again, the original example uses const docStyle = document.documentElement.style . I don't know the equivalent in React.

I am new to React and even CSS-In-JS in general. I would greatly appreciate it if someone can code out this example using React.

Answer 1

You can actually do this using the useRef (see the documentation for hooks and more specifically the useRef hook here - https://reactjs.org/docs/hooks-reference.html#useref ) hook without changing much of the code, not sure if you should do it this way but it works?

I have used an external SCSS file rather than emotion but you should be able to replicate pretty easily.

Here is the working example: https://codesandbox.io/s/cocky-neumann-kik51?fontsize=14