基于element-ui 动态换肤的代码详解

npm i sass-loader node-sass -D

npm i element-theme -D

npm i element-theme-chalk -D
# or from github
npm i https://github.com/ElementUI/theme-chalk -D

et -i // 默认的文件是element-variables.scss，也可以自定义文件名 et --init [file path]

import '../theme/index.css'
import ElementUI from 'element-ui'
import Vue from 'vue'

Vue.use(ElementUI)

ThemePicker.vue
<template>
  <el-tooltip effect="dark" content="theme" placement="bottom">
    <el-color-picker
    v-model="theme"
    class="theme-picker"
    size="small"
    popper-class="theme-picker-dropdown"/>
  </el-tooltip>
</template>
<script>
const version = require('element-ui/package.json').version // element-ui version from node_modules
const ORIGINAL_THEME = '#409EFF' // default color
export default {
  data() {
    return {
      chalk: '', // content of theme-chalk css
      theme: ORIGINAL_THEME
    }
  },
  watch: {
    theme(val, oldVal) {
      if (typeof val !== 'string') return
      const themeCluster = this.getThemeCluster(val.replace('#', ''))
      const originalCluster = this.getThemeCluster(oldVal.replace('#', ''))
      console.log(themeCluster, originalCluster)
      const getHandler = (variable, id) => {
        return () => {
          const originalCluster = this.getThemeCluster(ORIGINAL_THEME.replace('#', ''))
          const newStyle = this.updateStyle(this[variable], originalCluster, themeCluster)
          let styleTag = document.getElementById(id)
          if (!styleTag) {
            styleTag = document.createElement('style')
            styleTag.setAttribute('id', id)
            document.head.appendChild(styleTag)
          }
          styleTag.innerText = newStyle
        }
      }
      const chalkHandler = getHandler('chalk', 'chalk-style')
      if (!this.chalk) {
        const url = `https://unpkg.com/element-ui@${version}/lib/theme-chalk/index.css`
        this.getCSSString(url, chalkHandler, 'chalk')
      } else {
        chalkHandler()
      const styles = [].slice.call(document.querySelectorAll('style'))
        .filter(style => {
          const text = style.innerText
          return new RegExp(oldVal, 'i').test(text) && !/Chalk Variables/.test(text)
        })
      styles.forEach(style => {
        const { innerText } = style
        if (typeof innerText !== 'string') return
        style.innerText = this.updateStyle(innerText, originalCluster, themeCluster)
      })
      this.$message({
        message: '换肤成功',
        type: 'success'
  methods: {
    updateStyle(style, oldCluster, newCluster) {
      let newStyle = style
      oldCluster.forEach((color, index) => {
        newStyle = newStyle.replace(new RegExp(color, 'ig'), newCluster[index])
      return newStyle
    },
    getCSSString(url, callback, variable) {
      const xhr = new XMLHttpRequest()
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4 && xhr.status === 200) {
          this[variable] = xhr.responseText.replace(/@font-face{[^}] }/, '')
          callback()
      xhr.open('GET', url)
      xhr.send()
    getThemeCluster(theme) {
      const tintColor = (color, tint) => {
        let red = parseInt(color.slice(0, 2), 16)
        let green = parseInt(color.slice(2, 4), 16)
        let blue = parseInt(color.slice(4, 6), 16)
        if (tint === 0) { // when primary color is in its rgb space
          return [red, green, blue].join(',')
        } else {
          red  = Math.round(tint * (255 - red))
          green  = Math.round(tint * (255 - green))
          blue  = Math.round(tint * (255 - blue))
          red = red.toString(16)
          green = green.toString(16)
          blue = blue.toString(16)
          return `#${red}${green}${blue}`
      const shadeColor = (color, shade) => {
        red = Math.round((1 - shade) * red)
        green = Math.round((1 - shade) * green)
        blue = Math.round((1 - shade) * blue)
        red = red.toString(16)
        green = green.toString(16)
        blue = blue.toString(16)
        return `#${red}${green}${blue}`
      const clusters = [theme]
      for (let i = 0; i <= 9; i  ) {
        clusters.push(tintColor(theme, Number((i / 10).toFixed(2))))
      clusters.push(shadeColor(theme, 0.1))
      return clusters
  }
}
</script>

Navbar.vue
<template>
  <el-menu class="navbar" mode="horizontal">
    <hamburger 
      class="hamburger-container"
      :toggleClick="toggleSideBar"
      :isActive="!sidebar.opened">
    </hamburger>
    <div class="right-menu">
      <screenfull class="screenfull"></screenfull>
      <div class="lang">
        <el-dropdown>
          <i class="iconfont icon-language4"></i>
          <el-dropdown-menu slot="dropdown">
            <el-dropdown-item @click.native="toggleLang('zh')" :disabled="$i18n.locale == 'zh'">中文</el-dropdown-item>
            <el-dropdown-item @click.native="toggleLang('en')" :disabled="$i18n.locale == 'en'">English</el-dropdown-item>
          </el-dropdown-menu>
        </el-dropdown>
      </div>
      <theme-picker></theme-picker>
    </div>
  </el-menu>
</template>