javascript - Vue JS：如何从 vue 组件访问和更改 Css 根变量以切换 CSS 变量站点主题？

Question

我想在 Vue 组件中访问项目中的 css 根变量的值。例如，更改 10 个变量，包括颜色、边距和字体大小，通过按一个按钮为新值，然后按相同的按钮将变量更改为它们的（默认）原始值，实际上是在更改值项目中的css根变量。我怎样才能做到这一点 ？事实上，我想通过按一个按钮在黑暗和明亮之间切换。

这个想法的灵感来自下面链接的变化。链接里面的例子是用纯 JavaScript 脚本编写的，我想在 Next Js Framework 上开发的 Vue 项目中使用它。实现一个包含大约 10 个变量的网站，其值必须立即更改，按下按钮以在暗/亮模式下切换。

启发我的codepen链接:)

如何访问和更改 Css 根变量？

new Vue({
	el: "#theme",
	data: {
    return {
      dark: true,
      
    };
  },
  
  watch: {
    dark() {
    
      let bg = this.dark ? "#1b1b1b" : "#f5f5f5";
      let txtColor = this.dark ? "#999999" : "#333333";
      
      document.documentElement.style.setProperty("--bg", bg);
      document.documentElement.style.setProperty("--txt", txtColor);
      
    }
  }
});

:root{

--bg: white;
--txt: black;

}


body {
  background-color: var(--bg);
  color: var(--txt)
}
article {
  padding: 50px
}
article h2 {
  margin-top: 100px;
}

<div id="theme">

  <button @click="dark=!dark">dark</button>

<article>
  <h1>Hello World</h1>
  Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus elementum semper nisi. Aenean v
</article>

</div>

标签： javascriptvue.jsvue-componentnuxt.jscss-variables

Answer 1

您的示例中有语法错误，data但除此之外它可以正常工作。您想在页面加载后立即运行吗？

new Vue({
  el: "#theme",
  data() {
    return {
      dark: false,
      root: null
    };
  },
  mounted: function() {
    this.root = document.documentElement;
  },
  watch: {
    dark: {
      handler: function() {
        // because we are using this handler immideatly we need to wait for data changes using nextTick.
        this.$nextTick(() => {
          if (this.dark) {
            this.root.style.setProperty("--bg", "red");
            this.root.style.setProperty("--text", "black");
            this.root.style.setProperty("--padding", "10px");
            this.root.style.setProperty("--font", "1rem");
          } else {
            this.root.style.setProperty("--bg", "blue");
            this.root.style.setProperty("--text", "green");
            this.root.style.setProperty("--padding", "15px");
            this.root.style.setProperty("--font", "2rem");
          }
        })
      },
      immediate: true

    }
  }
});

:root {
  --bg: white;
  --bg-text: black;
  --padding: 5px;
  --font: 3rem;
}

body {
  background-color: var(--bg);
  color: var(--bg-text)
}

article {
  padding: 50px
}

article h2 {
  margin-top: 100px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="theme">

  <button @click="dark=!dark">dark</button>

  <article>
    <h1>Hello World</h1>
    Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium quis,
    sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus.
    Vivamus elementum semper nisi. Aenean v
  </article>

</div>