手配webpack4x，相关问题汇总

[ithack]

postcss所有插件介绍；
postcss-assets的demo:

/**
 * 引用图片，自动获取图片的宽高
 * @param  {string} $name [图片相对于img目录的位置]
 */
 @mixin image-background($name) {
    $url: '../assets/#{$name}.png';
    width: width($url);
    height: height($url);
    background-image: url($url);
    background-repeat: no-repeat;
    background-size: width($url) auto;
  }

sass 通用配置记录

/**
   * 引用图片，自动获取图片的 background-size
   * @param  {string} $url [图片的路径]
   */
  @mixin bg($url) {
    background-size: size($url);
    background-image: url($url);
    background-repeat: no-repeat;
  }
  
  /**
   * 文本截断 - text ellipsis
   * @param  {integer} $num [文本截断的行数]
   */
  @mixin text-line($num:1) {
    overflow: hidden;
    text-overflow: ellipsis;
  
    @if $num == 1 {
      white-space: nowrap;
    }
    @else {
      display: -webkit-box;
      -webkit-line-clamp: $num;
      -webkit-box-orient: vertical;
    }
  }
  
  /**
   * 清除浮动
   */
  @mixin clearfix() {
    &::after {
      content: '';
      display: block;
      clear: both;
    }
  }
  
  /**
   * 隐藏滚动条
   */
  @mixin hide-scrollbar() {
    &::-webkit-scrollbar {
      display: none;
      width: 0;
      height: 0;
    }
  }
  
  /**
   * 1像素边框
   * @param  {string} $position [边框位置，取值：top, bottom, left, right, full]
   * @param  {string} $borderColor [边框颜色]
   * @param  {number} $raidus [圆角]
   *
   * 例子：
   *   @include border(top, #ddd);
   *   @include border(full, #ddd, 2px);
   */
  @mixin border($position: full, $borderColor: #ddd, $radius: 0) {
    content: '';
    position: absolute;
    z-index: 1;
    pointer-events: none;
    background-color: $borderColor;
  
    @if $position == top {
      height: 1px;
      left: 0;
      right: 0;
      top: 0;
  
      @media only screen and (-webkit-min-device-pixel-ratio:2) {
        & {
          transform: scaleY(0.5);
          transform-origin: 50% 0%;
        }
      }
    } @else if $position == bottom {
      height: 1px;
      left: 0;
      right: 0;
      bottom: 0;
  
      @media only screen and (-webkit-min-device-pixel-ratio:2) {
        & {
          transform: scaleY(0.5);
          transform-origin: 50% 100%;
        }
      }
    } @else if $position == left {
      width: 1px;
      top: 0;
      bottom: 0;
      left: 0;
  
      @media only screen and (-webkit-min-device-pixel-ratio:2) {
        & {
          transform: scaleX(0.5);
          transform-origin: 0% 50%;
        }
      }
    } @else if $position == right {
      width: 1px;
      top: 0;
      bottom: 0;
      right: 0;
  
      @media only screen and (-webkit-min-device-pixel-ratio:2) {
        & {
          transform: scaleX(0.5);
          transform-origin: 100% 50%;
        }
      }
    } @else if $position == full {
      top: 0;
      bottom: 0;
      left: 0;
      right: 0;
      background: none;
      border: 1px solid #ddd;
      border-color: $borderColor;
  
      @if $radius != 0 {
        border-radius: $radius;
      }
  
      @media only screen and (-webkit-min-device-pixel-ratio:2) {
        & {
          right: -100%;
          bottom: -100%;
          transform: scale(0.5);
          transform-origin: 0% 0%;
  
          $radiusx2: null;
          @each $i in $radius {
            $radiusx2: append($radiusx2, $i * 2);
          }
  
          @if $radius != 0 {
            border-radius: $radiusx2;
          }
        }
      }
    }
  }