原生JavaScript实现电商详情页放大镜与图标列表组件

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>zoom</title>
</head>
<body>
 <script type="module">
  import Zoom from './js/Zoom.js';
  //图标数组
  let list=["a_icon.jpg","e_icon.jpg","f_icon.jpg","g_icon.jpg","h_icon.jpg","i_icon.jpg","j_icon.jpg",];
  init();
  function init(){
   let zoom=new Zoom(list,"./img/");
   zoom.appendTo("body");
  }
 </script>
</body>
</html>

import Utils from "./Utils.js";
import IconList from './IconList.js';
export default class Zoom{
 static styles=false;
 static small_width=450;
 static mask_width=303.75;
 static zoom_width=540;
 static SET_BG_IMG="set_bg_img";
 constructor(_list,_basePath){
  if(_basePath) _list=_list.map(item=>_basePath+item);
  //创建外层的div容器
  this.elem=this.createE();
  //监听事件，改变zoomSmall的背景图
  document.addEventListener(Zoom.SET_BG_IMG,e=>this.setBgImg(e));
  //创建下方的icon列表
  this.createIconList(_list,this.elem);
 }
 createE(){
  //创建外层div容器
  let div=Utils.createE("div");
  div.className="zoomContainer";
  div.innerHTML=`<div class="zoomSmall" id="zoomSmall"><div class="zoomMask" id="zoomMask"></div></div>
  <div class="zoomContent" id="zoomCont"></div>`;
  //设置样式
  Zoom.setStyle();
  //获取样式
  Utils.getIdElem(div,this);
  //监听鼠标滑入事件
  this.zoomSmall.addEventListener("mouseenter",e=>this.mouseHandler(e));
  return div;
 }
 appendTo(parent){
  Utils.appendTo(this.elem,parent);
 }
 setBgImg(e){
  //设置背景图片
  this.zoomSmall.style.backgroundImage=`url(${e.src})`;
  this.zoomCont.style.backgroundImage=`url(${e.src})`;
 }
 createIconList(list,parent){
  //创建下方icon图标列表
  let iconList=new IconList(list);
  Utils.appendTo(iconList.elem,parent);
 }
 mouseHandler(e){
  switch (e.type) {
   case "mouseenter":
    //鼠标滑入后，显示遮罩和右侧大图片
    this.zoomMask.style.display="block";
    this.zoomCont.style.display="block";
    //监听鼠标移动和滑出事件
    this.mouseHandlers=e=>this.mouseHandler(e);
    this.zoomSmall.addEventListener("mousemove",this.mouseHandlers);
    this.zoomSmall.addEventListener("mouseleave",this.mouseHandlers);
    break;
   case "mousemove":
    //遮罩移动
    this.zoomMaskMove(e);
    break;
   case "mouseleave":
    //鼠标滑出后，显示遮罩和右侧大图片
    this.zoomMask.style.display="none";
    this.zoomCont.style.display="none";
    //移除鼠标移动和滑出事件
    this.zoomSmall.removeEventListener("mousemove",this.mouseHandlers);
    this.zoomSmall.removeEventListener("mouseleave",this.mouseHandlers);
    break;
  }
 }
 zoomMaskMove(e){
  //遮罩移动
  let rect=this.elem.getBoundingClientRect();
  //计算let和top的值，等于鼠标的坐标-父容器的left值-遮罩的一半宽
  let x=e.clientX-rect.x-Zoom.mask_width/2;
  let y=e.clientY-rect.y-Zoom.mask_width/2;
  //判断left和top的范围
  if(x<0) x=0;
  if(x>Zoom.small_width-Zoom.mask_width) x=Zoom.small_width-Zoom.mask_width;
  if(y<0) y=0;
  if(y>Zoom.small_width-Zoom.mask_width) y=Zoom.small_width-Zoom.mask_width;
  this.zoomMask.style.left=x+"px";
  this.zoomMask.style.top=y+"px";
  //大图片移动
  this.zoomContMove(x,y);
 }
 zoomContMove(_x,_y){
  //计算大图片的背景定位，公式：zoom的宽/mask的宽=zoom的背景left值/mask的left值
  let x=-Zoom.zoom_width/Zoom.mask_width*_x;
  let y=-Zoom.zoom_width/Zoom.mask_width*_y;
  this.zoomCont.style.backgroundPosition=x+"px "+y+"px";
 }
 static setStyle(){
  //设置样式
  if(Zoom.styles) return;
  Zoom.styles=true;
  Utils.insertCss(".zoomContainer",{
   width:Zoom.small_width+"px",
   height:Zoom.small_width+"px",
   position:"relative"
  })
  Utils.insertCss(".zoomSmall",{
   width:Zoom.small_width+"px",
   height:Zoom.small_width+"px",
   border: "1px solid #000",
   backgroundSize: "100% 100%",
   position:"absolute",
   left:"0px",
   top:"0px"
  })
  Utils.insertCss(".zoomMask",{
   width: this.mask_width + "px",
   height: this.mask_width + "px",
   backgroundColor: "rgba(200,170,0,0.3)",
   position: "absolute",
   left: "0px",
   top: "0px",
   display: "none"
  })
  Utils.insertCss(".zoomContent",{
   width: this.zoom_width + "px",
   height: this.zoom_width + "px",
   border: "1px solid #ccc",
   position: "absolute",
   left: (this.small_width + 2) + "px",
   top: "0px",
   display: "none"
  })
 }
}

import Utils from "./Utils.js";
import Zoom from "./Zoom.js";
export default class IconList{
 static styles=false;
 static num=5;//每页显示的图标数
 static gap=0;//表示li的左右间距
 position=0;//当前显示的图标为第几页
 x=0;//列表的left值
 prepIcon;//上一个点击的图标
 static SET_BG_IMG="set_bg_img";
 constructor(list){
  this.list=list;
  this.elem=this.createE();
 }
 createE(){
  //创建外层容器
  let div=Utils.createE("div");
  div.className="iconContainer";
  div.innerHTML=`<img class="prevBtn" src="./img/prev.png"><div class="iconListCont">${this.createIcon()}</div><img class="nextBtn" src="./img/next.png">`;
  //设置css样式
  IconList.setStyles(this.list);
  //获取元素
  Utils.getIdElem(div,this);
  //外层容器监听点击事件
  div.addEventListener("click",e=>this.clickHandler(e));
  //图标列表监听鼠标滑过事件
  this.iconList.addEventListener("mouseover",e=>this.mouseHandler(e));
  //默认显示第一个图标的边框
  this.setIconState(this.iconList.firstElementChild);
  //默认显示第一个图片
  this.setBgImg(this.iconList.firstElementChild.firstElementChild);
  return div;
 }
 createIcon(){
  //创建图标列表
  let str=`<ul class="iconList clearfix" id="iconList">`;
  this.list.forEach(item=>{
   str+=`<li><img src="${item}"></li>`;
  })
  str+="</ul>";
  return str;
 }
 clickHandler(e){
  let src=e.target.src;
  //如果点击的不是左右按钮，直接跳出
  if(!/prev/.test(src)&&!/next/.test(src)) return;
  //每一个li的实际宽度，width+border+margin
  let liWidth=54+4+IconList.gap;
  //page为一共有几个整数页
  let page=Math.floor(this.list.length/IconList.num)-1;
  //remainder为最后不够一页的剩余图标数
  let remainder=this.list.length%IconList.num;
  if(/prev/.test(src)){
   //如果点击的是上一页按钮
   if(this.x===0) return;
   //移动到最后一页时
   if(this.position===0&&remainder>0){
    //移动的距离加等于li宽度*剩余图标数
    this.x+=liWidth*remainder;
   }
   else if(this.position<=page){
    this.position--;
    //移动的距离加等于li的宽度*每页显示的图标数（5个）
    this.x+=liWidth*IconList.num;
   }
  }else if(/next/.test(src)){
   //如果点击的是下一页按钮
   if(this.x===-(this.list.length-IconList.num)*liWidth) return;
   if(this.position===page&&remainder>0){
    //移动的距离减等于li宽度*剩余图标数
    this.x-=liWidth*remainder;
   }
   else if(this.position<page){
    this.position++;
    //移动的距离减等于li的宽度*每页显示的图标数（5个）
    this.x-=liWidth*IconList.num;
   }
  }
  //设置图标列表的left值
  this.iconList.style.left=this.x+"px";
 }
 mouseHandler(e){
  //如果滑过的不是Img标签，直接跳出
  if(e.target.constructor!==HTMLImageElement) return;
  //设置背景图片
  this.setBgImg(e.target);
  //设置当前滑过图标的样式
  this.setIconState(e.target.parentElement);
 }
 setIconState(target){
  //移除上一个滑过图标的active样式
  if(this.prepIcon) Utils.removeClass(this.prepIcon,"active");
  //将当前滑过的对象赋值给this.prepIcon
  this.prepIcon=target;
  //给当前滑过图标增加active样式
  Utils.addClass(this.prepIcon,"active");
 }
 setBgImg(target){
  //抛发事件，将当前图片的src传过去
  let src=target.src.replace("_icon","");
  let evt=new Event(IconList.SET_BG_IMG);
  evt.src=src;
  document.dispatchEvent(evt);
 }
 static setStyles(list){
  //设置样式
  if(IconList.styles) return;
  IconList.styles=true;
  Utils.insertCss(".iconContainer",{
   width:Zoom.small_width+2+"px",
   height: "58px",
   position: "absolute",
   top: Zoom.small_width+2+"px",
   left: "0px",
  })
  Utils.insertCss(".iconContainer>img",{
   width:"22px",
   height:"32px",
   cursor:"pointer",
   position:"absolute",
   top:"13px",
  })
  Utils.insertCss(".prevBtn",{
   left:"8px"
  })
  Utils.insertCss(".nextBtn",{
   right:"8px"
  })
  Utils.insertCss(".iconListCont",{
   width:Zoom.small_width-30*2+"px",
   height:"58px",
   position:"relative",
   left:"30px",
   overflow:"hidden"
  })
  IconList.gap=((Zoom.small_width-30*2)-(54+4)*IconList.num)/IconList.num;
  Utils.insertCss(".iconList",{
   width:(54+4+IconList.gap)*list.length+"px",
   listStyle:"none",
   padding:"0px",
   margin:"0px",
   position:"absolute",
   left:"0px",
   top:"0px",
   transition:"all .3s"
  })
  Utils.insertCss(".iconList li",{
   float:"left",
   width:"54px",
   height:"54px",
   margin:"0px "+IconList.gap/2+"px",
   cursor:"pointer",
   border:"2px solid transparent"
  })
  Utils.insertCss(".iconList li.active",{
   borderColor:"#f00"
  })
  Utils.insertCss(".iconList li>img",{
   width:"54px",
   height:"54px"
  })
  Utils.insertCss(".clearfix::after",{
   content:"\".\"",
   display:"block",
   height:"0px",
   clear:"both",
   overflow:"hidden",
   visibility:"hidden"
  })
 }
}

export default class Utils{
 static createE(elem,style,prep){
  elem=document.createElement(elem);
  if(style) for(let prop in style) elem.style[prop]=style[prop];
  if(prep) for(let prop in prep) elem[prop]=prep[prop];
  return elem;
 }
 static appendTo(elem,parent){
  if (parent.constructor === String) parent = document.querySelector(parent);
  parent.appendChild(elem);
 }
 static insertBefore(elem,parent){
  if(parent.constructor === String) parent=document.querySelector(parent);
  parent.insertBefore(elem,parent.firstElementChild);
 }
 static randomNum(min,max){
  return Math.floor(Math.random*(max-min)+min);
 }
 static randomColor(alpha){
  alpha=alpha||Math.random().toFixed(1);
  if(isNaN(alpha)) alpha=1;
  if(alpha>1) alpha=1;
  if(alpha<0) alpha=0;
  let col="rgba(";
  for(let i=0;i<3;i++){
   col+=Utils.randomNum(0,256)+",";
  }
  col+=alpha+")";
  return col;
 }
 static insertCss(select,styles){
  if(document.styleSheets.length===0){
   let styleS=Utils.createE("style");
   Utils.appendTo(styleS,document.head);
  }
  let styleSheet=document.styleSheets[document.styleSheets.length-1];
  let str=select+"{";
  for(var prop in styles){
   str+=prop.replace(/[A-Z]/g,function(item){
    return "-"+item.toLocaleLowerCase();
   })+":"+styles[prop]+";";
  }
  str+="}"
  styleSheet.insertRule(str,styleSheet.cssRules.length);
 }
 static getIdElem(elem,obj){
  if(elem.id) obj[elem.id]=elem;
  if(elem.children.length===0) return obj;
  for(let i=0;i<elem.children.length;i++){
   Utils.getIdElem(elem.children[i],obj);
  }
 }
 static addClass(elem,className){
  let arr=(elem.className+" "+className).match(/\S+/g);
  arr=arr.filter((item,index)=>arr.indexOf(item,index+1)<0)
  elem.className=arr.join(" ");
 }
 static removeClass(elem,className){
  if(!elem.className) return;
  let arr=elem.className.match(/\S+/g);
  let arr1=className.match(/\S+/g);
  arr1.forEach(item=>{
   arr=arr.filter(t=>t!==item)
  })
  elem.className=arr.join(" ");
 }
 static hasClass(elem,className){
  if(!elem.className) return false;
  let arr=elem.className.match(/\S+/g);
  let arr1=className.match(/\S+/g);
  let res;
  arr1.forEach(item=>{
   res= arr.some(it=>it===item)
  })
  return res;
 }
 static loadImg({list,basePath,callback}){
  if(!list || list.length===0) return;
  if(basePath) list=list.map(item=>basePath+item);
  let img=Utils.createE("img");
  img.data={
   list:list,
   callback:callback,
   resultList:[],
   num:0
  }
  img.addEventListener("load",Utils.loadImgHandler);
  img.src=list[img.data.num];
 }
 static loadImgHandler(e){
  let data=e.currentTarget.data;
  data.resultList.push(e.currentTarget.cloneNode(false));
  data.num++;
  if(data.num>data.list.length-1){
   e.currentTarget.removeEventListener("load",Utils.loadImgHandler);
   data.callback(data.resultList);
   data=null;
   return;
  }
  e.currentTarget.src=data.list[data.num];
 }
}