【日常记录】【CSS】SASS循环的使用

文章目录

1、引言

目前在任何项目框架中，都会有css 预处理器，目前一般使用 sass、less 这俩其中之一，它可以简化css的书写
Sass 是一款强化 CSS 的辅助工具，它在 CSS 语法的基础上增加了变量 (variables)、嵌套 (nested rules)、混合 (mixins)、导入 (inline imports) 等高级功能，这些拓展令 CSS 更加强大与优雅。使用 Sass 以及 Sass 的样式库（如 Compass）有助于更好地组织管理样式文件，以及更高效地开发项目。

2、安装

shell 复制代码

npm install -g sass

这样就是安装正确

sass --watch .\09_sass.scss 09_output.css

这个表示，监听 09_sass.scss 文件的改变，并且实时输出到 09_output.css 文件

3、举例

有 6个右箭头元素，如果写6边就很麻烦， sass 提供的 for 循环
@for 指令可以在限制的范围内重复输出格式，每次按要求（变量的值）对输出结果做出变动。这个指令包含两种格式：@for $var from through ，或者 @for$ var from to ，区别在于 through 与 to 的含义：当使用 through 时，条件范围包含与的值，而使用 to 时条件范围只包含的值不包含的值。另外， $var 可以是任何变量，比如$ i；< start > 和 < end > 必须是整数值。

html 复制代码

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="./09_output.css">
</head>

<body>
  <div class="box">
    鼠标移入
    <div class="item">
    </div>
    <div class="item">
    </div>
    <div class="item">
    </div>
    <div class="item">
    </div>
    <div class="item">
    </div>
    <div class="item">
    </div>
  </div>
</body>

</html>

css 复制代码

* {
  margin: 0;
  padding: 0;
}
svg {
  width: 100%;
  height: 100%;
}
body {
  height: 100vh;
  display: flex;
  align-items: center;
}
.box {
  position: relative;
  width: 100px;
  height: 100px;
  background-color: aqua;
  border-radius: 50%;
  text-align: center;
  line-height: 100px;
  cursor: pointer;
}
.box:hover .item {
  width: 100px;
}
.item {
  position: absolute;
  top: 0;
  left: 0;
  width: 0px;
  transition: all 0.4s;
  overflow: hidden;
  height: 40px;
  // transform: rotateX(90deg);
  background: url("data:image/svg+xml;base64,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")
    left center/30px 30px repeat;
}

$number: 6;
/* 32 */
@for $i from 1 through $number {
  .item:nth-child(#{$i}) {
    transform: translateX(#{$i * 100}px);
    top: #{$i * 20}px;
  }
}

4、参考链接

sass 中文官网