描述

打印指定的 dom 元素。
该方法由黄金苏同学提供

1.示例

打印table 打印body 打印table 之前、之后回调函数

<template>
  <div>
    <div style="display: flex; align-items: center; justify-content: center; padding: 10px 0">
      <el-button type="primary" size="small" @click="onPrintTable">打印table</el-button>
      <el-button type="primary" size="small" @click="onPrint">打印body</el-button>
      <el-button type="primary" size="small" @click="onPrintTableCb">打印table 之前、之后回调函数</el-button>
    </div>
    <el-table ref="table" :data="tableData" border style="width: 100%">
      <el-table-column prop="date" label="日期" width="180"> </el-table-column>
      <el-table-column prop="name" label="姓名" width="180"> </el-table-column>
      <el-table-column prop="address" label="地址"> </el-table-column>
    </el-table>
  </div>
</template>

<script>
import { print } from 'sf-utils2'

export default {
  data() {
    return {
      tableData: [
        {
          date: '2016-05-02',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        },
        {
          date: '2016-05-04',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1517 弄'
        },
        {
          date: '2016-05-01',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1519 弄'
        },
        {
          date: '2016-05-03',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1516 弄'
        }
      ]
    }
  },
  mounted() {
    console.log(this)
  },
  methods: {
    onPrint() {
      print(document.querySelector('body'))
    },

    onPrintTable() {
      print(this.$refs.table.$el)
    },

    onPrintTableCb() {
      print(this.$refs.table.$el, {
        printBeforeFn: () => {
          alert('打印前回调')
        },
        printDoneCallBack: () => {
          alert('打印后回调')
        }
      })
    }
  }
}
</script>

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2.入参说明

主入参

参数	说明	类型	是否必填	默认值
dom	目标元素	HTMLElement	是	-
options	选项配置，详情见下 👇	HTMLElement	-	-

options 对象

参数	说明	类型	是否必填	默认值
styleStr	样式 style	String	否
setDomHeightArr	需要设置高度的 dom 选择器集合，	Array	否
echartDomArr	echarts 元素 id 选择器集合	Array	否
printBeforeFn	打印前回调	Function	否
printDoneCallBack	打印后回调	Function	否

3.源码

源码，点开查看 👈

// 黄金苏提供
// 打印类属性、方法定义
class Print {
  constructor(dom, options) {
    options = options || {}
    if (!(this instanceof Print)) return new Print(dom, options)
    this.conf = {
      styleStr: '',
      setDomHeightArr: [], // 需要动态获取并设置高度的 元素
      echartDomArr: [], // echart dom
      printBeforeFn: null, // 打印前回调
      printDoneCallBack: null // 打印后回调
    }
    for (const key in this.conf) {
      if (key && options.hasOwnProperty(key)) {
        this.conf[key] = options[key]
      }
    }
    // debugger
    if (typeof dom === 'string') {
      this.dom = document.querySelector(dom)
    } else {
      this.dom = this.isDOM(dom) ? dom : dom.$el
    }
    if (this.conf.setDomHeightArr && this.conf.setDomHeightArr.length) {
      this.setDomHeight(this.conf.setDomHeightArr)
    }
    this.init()
  }
  /**
   * 初始化
   */
  init() {
    let content = this.getStyle() + this.getHtml()
    this.writeIframe(content)
  }
  /**
   * 配置属性扩展
   * @param {Object} obj
   * @param {Object} obj2
   */
  extendOptions(obj, obj2) {
    for (let k in obj2) {
      obj[k] = obj2[k]
    }
    return obj
  }
  /**
   复制原网页所有的样式
   */
  getStyle() {
    let str = '',
      styles = document.querySelectorAll('style,link')
    for (let i = 0; i < styles.length; i++) {
      str += styles[i].outerHTML
    }
    str += `<style>
.no-print{display:none;}${this.conf.styleStr}
</style>`
    return str
  }
  // 表单赋值
  getHtml() {
    let inputs = document.querySelectorAll('input')
    let textareas = document.querySelectorAll('textarea')
    let selects = document.querySelectorAll('select')
    // debugger
    for (let k = 0; k < inputs.length; k++) {
      if (inputs[k].type == 'checkbox' || inputs[k].type == 'radio') {
        if (inputs[k].checked == true) {
          inputs[k].setAttribute('checked', 'checked')
        } else {
          inputs[k].removeAttribute('checked')
        }
      } else if (inputs[k].type == 'text') {
        inputs[k].setAttribute('value', inputs[k].value)
      } else {
        inputs[k].setAttribute('value', inputs[k].value)
      }
    }

    for (let k2 = 0; k2 < textareas.length; k2++) {
      if (textareas[k2].type == 'textarea') {
        textareas[k2].innerHTML = textareas[k2].value
      }
    }

    for (let k3 = 0; k3 < selects.length; k3++) {
      if (selects[k3].type == 'select-one') {
        let child = selects[k3].children
        for (let i in child) {
          if (child[i].tagName == 'OPTION') {
            if (child[i].selected == true) {
              child[i].setAttribute('selected', 'selected')
            } else {
              child[i].removeAttribute('selected')
            }
          }
        }
      }
    }

    return this.dom.outerHTML
  }
  /**
   创建iframe
   */
  writeIframe(content) {
    let w,
      doc,
      iframe = document.createElement('iframe'),
      f = document.body.appendChild(iframe)

    iframe.id = 'myIframe'
    iframe.setAttribute('style', 'position:absolute;width:0;height:0;top:-10px;left:-10px;')
    w = f.contentWindow || f.contentDocument
    doc = f.contentDocument || f.contentWindow.document
    doc.open()
    doc.write(content)
    doc.close()
    let _this = this
    iframe.onload = function () {
      // 弹出前，回调
      if (_this.conf.printBeforeFn) {
        _this.conf.printBeforeFn({ doc })
      }

      _this.drawEchartImg(doc).then(() => {
        _this.toPrint(w)
        setTimeout(function () {
          document.body.removeChild(iframe)
          // 弹出后，回调
          if (_this.conf.printDoneCallBack) {
            _this.conf.printDoneCallBack()
          }
        }, 100)
      })
    }
  }
  /**
   * 项目用到echarts，需要获取图片，来打印
   * @param {Object} doc iframe window
   */
  drawEchartImg(doc) {
    return new Promise((resolve, reject) => {
      if (this.conf.echartDomArr && this.conf.echartDomArr.length > 0) {
        this.conf.echartDomArr.forEach(e => {
          const dom = doc.querySelector('#' + e.$el.id)
          const img = new Image()
          const w = dom.offsetWidth + 'px'
          const H = dom.offsetHeight + 'px'

          img.style.width = w
          img.style.height = H
          img.src = e.imgSrc
          dom.innerHTML = ''
          dom.appendChild(img)
        })
      }
      resolve()
    })
  }
  /*
   * 打印
   */
  toPrint(frameWindow) {
    try {
      setTimeout(function () {
        frameWindow.focus()
        try {
          if (!frameWindow.document.execCommand('print', false, null)) {
            frameWindow.print()
          }
        } catch (e) {
          frameWindow.print()
        }
        frameWindow.close()
      }, 10)
    } catch (err) {
      console.log('err', err)
    }
  }
  isDOM =
    typeof HTMLElement === 'object'
      ? function (obj) {
          return obj instanceof HTMLElement
        }
      : function (obj) {
          return obj && typeof obj === 'object' && obj.nodeType === 1 && typeof obj.nodeName === 'string'
        }
  /**
   * 设置指定dom元素高度，通过获取该dom元素现有高度，并设置
   * @param {Array} arr
   */
  setDomHeight(arr) {
    if (arr && arr.length) {
      arr.forEach(name => {
        const domArr = document.querySelectorAll(name)
        // debugger
        domArr.forEach(dom => {
          dom.style.height = dom.offsetHeight + 'px'
        })
      })
    }
  }
}

/**
 * 打印dom
 * @param dom
 * @param options
 * @returns {Print}
 */
function print(dom, options = {}) {
  return new Print(dom, options)
}