修改元素：在CSS规则编程之前在React中

问题描述

我有一个元素：之前样式必须根据计算进行修改。

I have an element whose :before style has to be modified based on calculations.

export class Content extends React.Component {
    render() {
        return (
            <div className="ring-base">
               <div className="ring-left" style={{/* Change here */}}></div>
               <div className="ring-right" style={{/* Change here */}}></div>
               <div className="ring-cover">
                   <div className="ring-text">10%</div>
               </div>
            </div>
        );
    }
}

CSS代码：

.ring-base {
    position: absolute;
    height: 200px;
    width: 200px;
    border-radius: 50%;
    background: red;
    transform: rotate(90deg);
    overflow:hidden;
}
.ring-cover {
    position: absolute;
    height: 180px;
    width: 180px;
    background: #fff;
    border-radius: 50%;
    top: 5%;
    left: 5%;
}

.ring-cover .ring-text {
    position: absolute;

    width: 100%;
    height: 100%;
    text-align: center;
    font-size: 2em;
    display: flex;
    justify-content:center;
    align-content:center;
    flex-direction:column;
    transform: rotate(-90deg);
}

.ring-right, .ring-left {
    height: 100px;
    width: 200px;
    overflow: hidden;
    position: absolute;  
}

.ring-right:before, .ring-left:before {
    height: inherit;
    width: inherit;
    position: absolute;
    content: "";
    border-radius: 100px 100px 0 0;
    background-color: grey;
    transform: rotate(0deg);
}

.ring-right {
    -webkit-transform-origin: 50% 0%;
    -moz-transform-origin: 50% 0%;
    -ms-transform-origin: 50% 0%;
    transform-origin: 50% 0%;
    transform: rotateZ(0deg);
}

.ring-left {
    transform: rotate(180deg);
    -webkit-transform-origin: 50% 100%;
    -moz-transform-origin: 50% 100%;
    -ms-transform-origin: 50% 100%;
    transform-origin: 50% 100%;
}

.ring-right:before {
    -webkit-transform-origin: 50% 100%;
    -moz-transform-origin: 50% 100%;
    -ms-transform-origin: 50% 100%;
    transform-origin: 50% 100%;
    transform: rotate(0deg);
}

.ring-left:before {
    -webkit-transform-origin: 50% 100%;
    -moz-transform-origin: 50% 100%;
    -ms-transform-origin: 50% 100%;
    transform-origin: 50% 100%;
    -webkit-transform: rotate(0deg);
    -moz-transform: rotate(0deg);
    -ms-transform: rotate(0deg);
    transform: rotate(0deg);

}

要求是能够更新转换属性 .ring-left：在之前和 .ring-right：在之前通过ReactJS。

The ask is to be able to update the transform property for .ring-left:before and .ring-right:before via ReactJS.

如果有办法不更新：在类之前并将CSS更改为不使用：之前，然后也建议。

If there is a way to not update the :before class and change the CSS to not make use of :before at all, then do suggest that as well.

推荐答案

您可以迭代文档.styleSheets ，设置 .style .cssRules 其中。 selectorText 匹配伪选择器

You can iterate document.styleSheets, set .style of .cssRules where .selectorText matches pseudo selector

let sheets = document.styleSheets;
let selector = "div::before";
let replacementContent = '"after"';
for (let sheet of sheets) {
  for (let rule of sheet.cssRules) {
    if (rule.selectorText === selector) {
      rule.style["content"] = replacementContent;
    }
  }
}

div:before {
  content: "before";
  color: red;
  font-weight: bold;
  text-align: center;
  text-shadow: 2px 2px 2px #000;
  background: green;
  width: 50px;
  height: 50px;
  display: block;
}

<div></div>

这篇关于修改元素：在CSS规则编程之前在React中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！