1、代码简化

1.1、简化媒介查询

@mixin flex{
    display: flex;
    justify-content: center;
    align-items: center;
}
.header{
    width: 100%;
    @include flex;//可以这样引用
}

//加入参数
@mixin flex($layout){
    display: flex;
    justify-content: $layout;
    align-items: $layout;
}
.header{
    width: 100%;
    @include flex(start);
}

@mixin flex($layout){
    display: flex;
    justify-content: $layout;
    align-items: $layout;
    @content;//就是花括号里传过来的内容
}
.header{
    width: 100%;
    @include flex(start){
        gap: 10px;
    };
}

@mixin respondTo($name,$minWith,$maxWith) {
    @if $name== '手机' {
        @media(min-width: 320px) and (max-width: 480px) {
            @content
        }
    } @else if $name=='平板' {
        @media(min-width: 481px) and (max-width: 768px) {
            @content
        }
    }
}

.header {
    @include respondTo('手机') {
        height: 50px;
    }
    @include respondTo('平板') {
        height: 80px;
    }
}

$breakPoints:(
    'phone':(320px,480px),
    'pad':(481px,768px),
    'notebook':(769px,1024px),
    'desktop':(1025px,1200px),
    'tv':1201px,
);
@mixin respondTo($name,$minWith,$maxWith) {
    $bp:map-get($breakPoints,$name);//保存变量bp
    @if type-of($bp)=='list'{
        $min:nth($bp,1);
        $max:nth($bp,2);
        @media(min-width: $min) and (max-width: $max) {
            @content
        }
    } @else {
        @media(min-width: $bp) {
            @content
        }
    }
}

完全体

$breakPoints:(
    'phone':(320px,480px),
    'pad':(481px,768px),
    'notebook':(769px,1024px),
    'desktop':(1025px,1200px),
    'tv':1201px,
);
@mixin respondTo($name,$minWith,$maxWith) {
    $bp:map-get($breakPoints,$name);//保存变量bp
    @if type-of($bp)=='list'{
        $min:nth($bp,1);
        $max:nth($bp,2);
        @media(min-width: $min) and (max-width: $max) {
            @content
        }
    } @else {
        @media(min-width: $bp) {
            @content
        }
    }
}

.header {
    @include respondTo('phone') {
        height: 50px;
    }
    @include respondTo('pad') {
        height: 60px;
    }
    @include respondTo('notebook') {
        height: 80px;
    }
}

1.2、@for、@while、@each、自定义函数

@for
@for的用法不同于JS，Sass中的for有两种格式：

• @for $i from n through m 表示变量i 的范围是[n, m];
• @for $i from n to m 表示变量i 的范围是[n, m);
  
  @while
  
  @each
  
  自定义函数
  

1.3、sass里的数学函数

目标需求

原样

sass编译成css，终端输入，-w表示监控源文件变化

sass index.scss index.css -x

布局位置其实就是角度不一样

@use 'sass:math';
$r:120px;
.menu-item:nth-child(1) {
    $deg:45deg;
    $x:$r * math.sin($deg);
    $y:-$r * math.cos($deg);
    //@debug $x;//可在控制台打印
    transform: translate($x,$y);
}

@use 'sass:math';

$r: 120px;
$n: 6; //数量
$step: 360deg/$n; //数量
@for $i from 1 through $n {
    .menu-item:nth-child(#{$i}) {
        $deg: $step*($i-1);
        $x: $r * math.sin($deg);
        $y: $r * math.cos($deg);
        transform: translate($x, $y);
    }
}

2、其他