vue 中使用print.js导出pdf操作

// 打印类属性、方法定义
/* eslint-disable */
const Print = function (dom, options) {
 if (!(this instanceof Print)) return new Print(dom, options);
 this.options = this.extend({
 'noPrint': '.no-print'
 }, options);
 if ((typeof dom) === "string") {
 this.dom = document.querySelector(dom);
 } else {
 this.isDOM(dom)
 this.dom = this.isDOM(dom) ? dom : dom.$el;
 }
 this.init();
};
Print.prototype = {
 init: function () {
 var content = this.getStyle() + this.getHtml();
 this.writeIframe(content);
 },
 extend: function (obj, obj2) {
 for (var k in obj2) {
  obj[k] = obj2[k];
 }
 return obj;
 },
 getStyle: function () {
 var str = "",
  styles = document.querySelectorAll('style,link');
 for (var i = 0; i < styles.length; i++) {
  str += styles[i].outerHTML;
 }
 str += "<style>" + (this.options.noPrint ? this.options.noPrint : '.no-print') + "{display:none;}</style>";
 str += "<style>html,body,div,#preview-main,.report{width:100%!important;height: auto!important;font-size:14px}</style>";
 return str;
 },
 getHtml: function () {
 var inputs = document.querySelectorAll('input');
 var textareas = document.querySelectorAll('textarea');
 var selects = document.querySelectorAll('select');
 var canvass = document.querySelectorAll('canvas');
 for (var 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 (var k2 = 0; k2 < textareas.length; k2++) {
  if (textareas[k2].type == 'textarea') {
  textareas[k2].innerHTML = textareas[k2].value
  }
 }
 for (var k3 = 0; k3 < selects.length; k3++) {
  if (selects[k3].type == 'select-one') {
  var child = selects[k3].children;
  for (var i in child) {
   if (child[i].tagName == 'OPTION') {
   if (child[i].selected == true) {
    child[i].setAttribute('selected', "selected")
   } else {
    child[i].removeAttribute('selected')
   }
   }
  }
  }
 }
 //canvass echars图表转为图片
 for (var k4 = 0; k4 < canvass.length; k4++) {
  var imageURL = canvass[k4].toDataURL("image/png");
  var img = document.createElement("img");
  img.src = imageURL;
  img.setAttribute('style', 'max-width: 100%;');
  img.className = 'isNeedRemove'
  // canvass[k4].style.display = 'none'
  // canvass[k4].parentNode.style.width = '100%'
  // canvass[k4].parentNode.style.textAlign = 'center'
  canvass[k4].parentNode.insertBefore(img,canvass[k4].nextElementSibling);
 }
 return this.dom.outerHTML;
 },
 writeIframe: function (content) {
 var w, doc, iframe = document.createElement('iframe'),
  f = document.body.appendChild(iframe);
 iframe.id = "myIframe";
 //iframe.style = "position:absolute;width:0;height:0;top:-10px;left:-10px;";
 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();
 // 避免重复打印echarts
 var removes = document.querySelectorAll('.isNeedRemove');
 for (var k = 0; k < removes.length; k++) {
  removes[k].parentNode.removeChild(removes[k]);
 }
 var _this = this
 iframe.onload = function(){
  _this.toPrint(w);
  setTimeout(function () {
  document.body.removeChild(iframe)
  }, 100)
 }
 },
 toPrint: function (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';
 }
};
const MyPlugin = {}
MyPlugin.install = function (Vue, options) {
 // 4. 添加实例方法
 Vue.prototype.$print = Print
}
export default MyPlugin

img.className = 'isNeedRemove'
canvass[k4].parentNode.insertBefore(img,canvass[k4].nextElementSibling);
var removes = document.querySelectorAll('.isNeedRemove');

//调用系统打印机
print () {
 this.$print(this.$refs.print) // 使用
},

 <!-- 预览 -->
<Modal v-model="previewModal" fullscreen :mask-closable="false" :closable="false">
 <preview ref="print" :previewEditOldForm="previewEditForm"></preview>
 <div slot="footer" class="btn">
  <Button type="text" @click="closePreview">关闭</Button>
  <Button type="primary" @click="print">打印</Button>
 </div>
</Modal> 

import Preview from '../operation_report/Preview'
export default {
 components: {
   Preview
 }
}

export default {
 data() {
 return{
 previewEditForm: {},
 }
 }
}

// 父组件向子组件传值
 on: {
  click: () => {
   // 父组件向子组件传值
   this.previewEditForm = params.row;
   setTimeout(() => {
    this.$refs.print.queryById();
    this.$refs.print.eventOverviews();
    this.previewModal=true;
   }, 2000)
  }
 }

<style scoped>
 @media print {
  .btn{
   display: none;
  }
 }
</style>