简单实现前端打印功能

实现代码

print.js

// print.js
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{height: auto!important;}</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');
            }
          }
        }
      }
    }
    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].parentNode.insertBefore(img, canvass[k4].nextElementSibling);
    }

    return this.dom.outerHTML;
  },
  wrapperRefDom: function (refDom) {
    let prevDom = null;
    let currDom = refDom;
    while (currDom && currDom.tagName.toLowerCase() !== 'body') {
      if (prevDom) {
        let element = currDom.cloneNode(false);
        element.appendChild(prevDom);
        prevDom = element;
      } else {
        prevDom = currDom.cloneNode(true);
      }

      currDom = currDom.parentElement;
    }

    return currDom.tagName.toLowerCase() === 'body' ? currDom : prevDom;
  },

  writeIframe: function (content) {
    var 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();
    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.error('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 Print;

main.js引用,挂载方法到实例上

import print from './utils/print';
Vue.prototype.$print = print;

页面使用

<template>
  <div>
    // 自己的组件
    <component ref='name'><component/>
    // 正常元素
    <div ref='printBox'>
    正常元素
    </div>
  </div>
</template>

<script>
  export default {
    name:'Demo'
    methods:{
      printHandle(){
        // 如果是正常元素不需要添加$el
        this.print(this.$refs.printBox)
        // 如果是模板组件得拿到对应的元素实例而不是vue组件实例
        this.print(this.$refs.name.$el)
      }
    }
  }
</script>

<style lang="scss" scoped>

</style>