功能需求
1.四张图片循环播放,每张图片停留若干时间
2.当用户点击左右两边的小箭头时,图片分别切换到上一张/下一张
3.当用户点击底部的小圆点时,则立即跳到小圆点顺序所对应的那张图片
方法一
html
<div id="my-slider" class="slider-list">
<ul>
<li class="slider-list__item--selected">
<img src="https://p5.ssl.qhimg.com/t0119c74624763dd070.png"/>
</li>
<li class="slider-list__item">
<img src="https://p4.ssl.qhimg.com/t01adbe3351db853eb3.jpg"/>
</li>
<li class="slider-list__item">
<img src="https://p2.ssl.qhimg.com/t01645cd5ba0c3b60cb.jpg"/>
</li>
<li class="slider-list__item">
<img src="https://p4.ssl.qhimg.com/t01331ac159b58f5478.jpg"/>
</li>
</ul>
<a class="slide-list__next"></a> //下一张
<a class="slide-list__previous"></a> //上一张
<div class="slide-list__control"> //小圆点
<span class="slide-list__control-buttons--selected"></span>
<span class="slide-list__control-buttons"></span>
<span class="slide-list__control-buttons"></span>
<span class="slide-list__control-buttons"></span>
</div>
</div>
用列表元素作为图片的容器,用<a>分别表示“下一张”和“上一张”的控制,用四个<span>元素表示底部的四个小圆点的控制
CSS
#my-slider{
position: relative;
width: 790px;
height: 340px;
}
.slider-list ul{
list-style-type:none;
position: relative;
width: 100%;
height: 100%;
padding: 0;
margin: 0;
}
.slider-list__item,
.slider-list__item--selected{
position: absolute; //将4张照片重叠显示在同一个位置
transition: opacity 1s; //设置图片透明度变化的动画,时间为1秒
opacity: 0;
text-align: center;
}
.slider-list__item--selected{ //状态为slider-list__item--selected为不透明
transition: opacity 1s;
opacity: 1;
}
.slide-list__control{
position: relative;
display: table;
background-color: rgba(255, 255, 255, 0.5);
padding: 5px;
border-radius: 12px;
bottom: 30px;
margin: auto;
}
.slide-list__next,
.slide-list__previous{
display: inline-block;
position: absolute;
top: 50%;
margin-top: -25px;
width: 30px;
height:50px;
text-align: center;
font-size: 24px;
line-height: 50px;
overflow: hidden;
border: none;
background: transparent;
color: white;
background: rgba(0,0,0,0.2); //设置为半透明
cursor: pointer;
opacity: 0; //初始状态为透明
transition: opacity .5s; //设置透明度变化的动画,时间为0.5秒
}
.slide-list__previous {
left: 0; //定位在slider元素的最左边
}
.slide-list__next {
right: 0; //定位在slider元素的最右边
}
#my-slider:hover .slide-list__previous {
opacity: 1;
}
#my-slider:hover .slide-list__next {
opacity: 1;
}
.slide-list__previous:after {
content: '<';
}
.slide-list__next:after {
content: '>';
}
.slide-list__control-buttons,
.slide-list__control-buttons--selected{
display: inline-block;
width: 15px;
height: 15px;
border-radius: 50%;
margin: 0 5px;
background-color: white;
cursor: pointer;
}
.slide-list__control-buttons--selected { //当选择后,小圆点的颜色为红色
background-color: red;
}
:after 选择器在被选元素的内容后面插入内容。使用 content 属性来指定要插入的内容。
JS
class Slider{
constructor(id, cycle = 3000){
{container}表示放置这4张图片的父容器
this.container = document.getElementById(id);
this.items = this.container.querySelectorAll('.slider-list__item, .slider-list__item--selected');
this.cycle = cycle;
const controller = this.container.querySelector('.slide-list__control');
if(controller){
const buttons = controller.querySelectorAll('.slide-list__control-buttons, .slide-list__control-buttons--selected');
controller.addEventListener('mouseover', evt=>{//当鼠标移入
const idx = Array.from(buttons).indexOf(evt.target);
if(idx >= 0){
this.slideTo(idx);
this.stop();//停止自动循环播放
}
});
controller.addEventListener('mouseout', evt=>{//当鼠标移出
this.start();//开始自动循环播放
});
//注册slide事件,将选中的图片和小圆点设置为selected状态
this.container.addEventListener('slide', evt => {
const idx = evt.detail.index
const selected = controller.querySelector('.slide-list__control-buttons--selected');
if(selected) selected.className = 'slide-list__control-buttons';
buttons[idx].className = 'slide-list__control-buttons--selected';
})
}
const previous = this.container.querySelector('.slide-list__previous');
if(previous){
previous.addEventListener('click', evt => {
this.stop();
this.slidePrevious();
this.start();
evt.preventDefault();
});
}
const next = this.container.querySelector('.slide-list__next');
if(next){
next.addEventListener('click', evt => {
this.stop();
this.slideNext();
this.start();
evt.preventDefault();
});
}
}
//通过选择器'.slider__item--selected'获得被选中的元素
getSelectedItem(){
let selected = this.container.querySelector('.slider-list__item--selected');
return selected
}
//返回选中的元素在items数组中的位置
getSelectedItemIndex(){
return Array.from(this.items).indexOf(this.getSelectedItem());
}
//切换显示idx指示位置的图片
slideTo(idx){
let selected = this.getSelectedItem();
if(selected){ //将之前选择的图片标记为普通状态
selected.className = 'slider-list__item';
}
let item = this.items[idx];
if(item){ //将当前选中的图片标记为选中状态
item.className = 'slider-list__item--selected';
}
const detail = {index: idx}
const event = new CustomEvent('slide', {bubbles:true, detail})
this.container.dispatchEvent(event)
//当slideTo方法执行后,这个方法就会触发一次slide事件,然后在这个事件中,更新底部小圆点的状态,让小圆点的状态和各自的图片状态对应起来
}
slideNext(){
//将下一张图片标记为选中状态
let currentIdx = this.getSelectedItemIndex();
let nextIdx = (currentIdx + 1) % this.items.length;
this.slideTo(nextIdx);
}
//将上一张图片标记为选中状态
slidePrevious(){
let currentIdx = this.getSelectedItemIndex();
let previousIdx = (this.items.length + currentIdx - 1) % this.items.length;
this.slideTo(previousIdx);
}
//启动了一个计时器,每隔cycle秒执行一次slideNext()
start(){
this.stop();
this._timer = setInterval(()=>this.slideNext(), this.cycle);
}
//停止计时器
stop(){
clearInterval(this._timer);
}
}
const slider = new Slider('my-slider');
slider.start();
querySelector()方法返回文档中匹配指定 CSS 选择器的第一个元素。
indexOf() 方法可返回某个指定的字符串值在字符串中首次出现的位置。
querySelectorAll() 方法返回文档中匹配指定 CSS 选择器的所有元素
addEventListener() 方法用于向指定元素添加事件句柄。
preventDefault() 方法阻止元素发生默认的行为(例如,当点击提交按钮时阻止对表单的提交)。
内置的事件会由浏览器根据某些操作进行触发,自定义的事件就需要人工触发。dispatchEvent 函数就是用来触发自定义事件。
缺点
缺少可扩展性
方法二:组件的插件化
插件化:将用户控制组件从slider组件中剥离出来,做成插件,这样才能提高slider组件的可扩展性
在图片轮播组件中,用户的控制组件分为三个部分:图片下部的小圆点以及左右翻页按钮。我们分别用controller、previous、next三个变量来分别处理他们。
html
<div id="my-slider" class="slider-list">
<ul>
<li class="slider-list__item--selected">
<img src="https://p5.ssl.qhimg.com/t0119c74624763dd070.png"/>
</li>
<li class="slider-list__item">
<img src="https://p4.ssl.qhimg.com/t01adbe3351db853eb3.jpg"/>
</li>
<li class="slider-list__item">
<img src="https://p2.ssl.qhimg.com/t01645cd5ba0c3b60cb.jpg"/>
</li>
<li class="slider-list__item">
<img src="https://p4.ssl.qhimg.com/t01331ac159b58f5478.jpg"/>
</li>
</ul>
<a class="slide-list__next"></a>
<a class="slide-list__previous"></a>
<div class="slide-list__control">
<span class="slide-list__control-buttons--selected"></span>
<span class="slide-list__control-buttons"></span>
<span class="slide-list__control-buttons"></span>
<span class="slide-list__control-buttons"></span>
</div>
</div>
css
#my-slider{
position: relative;
display: inline-block;
width: 790px;
height: 340px;
}
.slider-list ul{
list-style-type:none;
position: relative;
width: 100%;
height: 100%;
padding: 0;
margin: 0;
}
.slider-list__item,
.slider-list__item--selected{
position: absolute;
transition: opacity 1s;
opacity: 0;
text-align: center;
}
.slider-list__item--selected{
transition: opacity 1s;
opacity: 1;
}
.slide-list__control{
position: relative;
display: table;
background-color: rgba(255, 255, 255, 0.5);
padding: 5px;
border-radius: 12px;
bottom: 30px;
margin: auto;
}
.slide-list__next,
.slide-list__previous{
display: inline-block;
position: absolute;
top: 50%;
margin-top: -25px;
width: 30px;
height:50px;
text-align: center;
font-size: 24px;
line-height: 50px;
overflow: hidden;
border: none;
background: transparent;
color: white;
background: rgba(0,0,0,0.2);
cursor: pointer;
opacity: 0;
transition: opacity .5s;
}
.slide-list__previous {
left: 0;
}
.slide-list__next {
right: 0;
}
#my-slider:hover .slide-list__previous {
opacity: 1;
}
#my-slider:hover .slide-list__next {
opacity: 1;
}
.slide-list__previous:after {
content: '<';
}
.slide-list__next:after {
content: '>';
}
.slide-list__control-buttons,
.slide-list__control-buttons--selected{
display: inline-block;
width: 15px;
height: 15px;
border-radius: 50%;
margin: 0 5px;
background-color: white;
cursor: pointer;
}
.slide-list__control-buttons--selected {
background-color: red;
}
JS
class Slider{
constructor(id, cycle = 3000){
this.container = document.getElementById(id);
this.items = this.container.querySelectorAll('.slider-list__item, .slider-list__item--selected');
this.cycle = cycle;
}
//在sliders类的构造器中,我们将注册控制流程的代码移除,增加了一个新的方法叫registerPlugins,这个方法接受一组参数plugins,每个plugins本身是一个初始化函数,可以做任何事情
registerPlugins(...plugins){
plugins.forEach(plugin => plugin(this));
}
//通过选择器'.slider-list__item--selected'获得被选中的元素
getSelectedItem(){
const selected = this.container.querySelector('.slider-list__item--selected');
return selected
}
//返回选中的元素在items数组中的位置
getSelectedItemIndex(){
return Array.from(this.items).indexOf(this.getSelectedItem());
}
slideTo(idx){
const selected = this.getSelectedItem();
if(selected){
selected.className = 'slider-list__item';
}
const item = this.items[idx];
if(item){
item.className = 'slider-list__item--selected';
}
const detail = {index: idx}
const event = new CustomEvent('slide', {bubbles:true, detail})
this.container.dispatchEvent(event)
}
//将下一张图片标记为选中状态
slideNext(){
const currentIdx = this.getSelectedItemIndex();
const nextIdx = (currentIdx + 1) % this.items.length;
this.slideTo(nextIdx);
}
//将上一张照片标记为选中状态
slidePrevious(){
const currentIdx = this.getSelectedItemIndex();
const previousIdx = (this.items.length + currentIdx - 1) % this.items.length;
this.slideTo(previousIdx);
}
addEventListener(type, handler){
this.container.addEventListener(type, handler)
}
start(){
this.stop();
this._timer = setInterval(()=>this.slideNext(), this.cycle);
}
stop(){
clearInterval(this._timer);
}
}
//小圆点控件
function pluginController(slider){
const controller = slider.container.querySelector('.slide-list__control');
if(controller){
const buttons = controller.querySelectorAll('.slide-list__control-buttons, .slide-list__control-buttons--selected');
controller.addEventListener('mouseover', evt=>{
const idx = Array.from(buttons).indexOf(evt.target);
if(idx >= 0){
slider.slideTo(idx);
slider.stop();
}
});
controller.addEventListener('mouseout', evt=>{
slider.start();
});
slider.addEventListener('slide', evt => {
const idx = evt.detail.index
const selected = controller.querySelector('.slide-list__control-buttons--selected');
if(selected) selected.className = 'slide-list__control-buttons';
buttons[idx].className = 'slide-list__control-buttons--selected';
});
}
}
//向前控件
function pluginPrevious(slider){
const previous = slider.container.querySelector('.slide-list__previous');
if(previous){
previous.addEventListener('click', evt => {
slider.stop();
slider.slidePrevious();
slider.start();
evt.preventDefault();
});
}
}
//向右控件
function pluginNext(slider){
const next = slider.container.querySelector('.slide-list__next');
if(next){
next.addEventListener('click', evt => {
slider.stop();
slider.slideNext();
slider.start();
evt.preventDefault();
});
}
}
const slider = new Slider('my-slider');
slider.registerPlugins(pluginController, pluginPrevious, pluginNext);
slider.start();
pluginController、pluginPrevious、pluginNext分别表示小圆点控制和左右翻页控制插件。每个插件接受一个Slider的实例。然后,将各自的用户事件注册在对应的插件上。
我们在Slider.registerPlugins对象方法里,,给每个plugin(即插件)传入当前的slider对象实例。在插件的初始化函数时,我们就可以拿到这个slider对象。这种将依赖对象传入插件初始化函数的方式,叫做依赖注入。
优点
欲去掉图片下方的小圆点控制时:
我们只需要简单将小圆点从插件注册中去掉,完全不需要修改组件代码
增加“试试手气”:
html
<button class="lucky">试试手气</button>
JS
//创建插件
function pluginLucky(slider){
const luckyBtn=document.querySelector('.lucky');
if(luckyBtn){
luckyBtn.addEventListener('click',evt=>{
slider.stop();
slider.sliderTo(Math.floor(Math.random()*slider.items.length));
slider.start();
evt.preventDefault();
});
}
}
//将插件注册到slider中
方法三:组件的模块化
使用自定义事件来解耦(改变状态) 解耦:将控制元素抽取成插件 把插件的逻辑和组件的逻辑分离开
html
<div id="my-slider" class="slider-list"></div>
css
#my-slider{
position: relative;
width: 790px;
height: 340px;
}
.slider-list ul{
list-style-type:none;
position: relative;
width: 100%;
height: 100%;
padding: 0;
margin: 0;
}
.slider-list__item,
.slider-list__item--selected{
position: absolute;
transition: opacity 1s;
opacity: 0;
text-align: center;
}
.slider-list__item--selected{
transition: opacity 1s;
opacity: 1;
}
.slide-list__control{
position: relative;
display: table;
background-color: rgba(255, 255, 255, 0.5);
padding: 5px;
border-radius: 12px;
bottom: 30px;
margin: auto;
}
.slide-list__next,
.slide-list__previous{
display: inline-block;
position: absolute;
top: 50%;
margin-top: -25px;
width: 30px;
height:50px;
text-align: center;
font-size: 24px;
line-height: 50px;
overflow: hidden;
border: none;
background: transparent;
color: white;
background: rgba(0,0,0,0.2);
cursor: pointer;
opacity: 0;
transition: opacity .5s;
}
.slide-list__previous {
left: 0;
}
.slide-list__next {
right: 0;
}
#my-slider:hover .slide-list__previous {
opacity: 1;
}
#my-slider:hover .slide-list__next {
opacity: 1;
}
.slide-list__previous:after {
content: '<';
}
.slide-list__next:after {
content: '>';
}
.slide-list__control-buttons,
.slide-list__control-buttons--selected{
display: inline-block;
width: 15px;
height: 15px;
border-radius: 50%;
margin: 0 5px;
background-color: white;
cursor: pointer;
}
.slide-list__control-buttons--selected {
background-color: red;
}
JS
class Slider{
constructor(id, opts = {images:[], cycle: 3000}){
this.container = document.getElementById(id);
this.options = opts;
//利用数据源渲染自己的HTML
this.container.innerHTML = this.render();
this.items = this.container.querySelectorAll('.slider-list__item, .slider-list__item--selected');
this.cycle = opts.cycle || 3000;
this.slideTo(0);
}
//用于渲染Slider组件的HTML部分
render(){
const images = this.options.images;
const content = images.map(image => `
<li class="slider-list__item">
<img src="${image}"/>
</li>
`.trim());
return `<ul>${content.join('')}</ul>`;
}
registerPlugins(...plugins){
plugins.forEach(plugin => {
const pluginContainer = document.createElement('div');
// Slider组件为每个plugin创建了一个class='.slider-list__plugin'的容器
pluginContainer.className = '.slider-list__plugin';
//将插件的HTML元素添加到这个容器中
pluginContainer.innerHTML = plugin.render(this.options.images);
//把这个容器添加到Slider组件中
this.container.appendChild(pluginContainer);
plugin.initialized(this);
});
}
getSelectedItem(){
const selected = this.container.querySelector('.slider-list__item--selected');
return selected
}
getSelectedItemIndex(){
return Array.from(this.items).indexOf(this.getSelectedItem());
}
slideTo(idx){
const selected = this.getSelectedItem();
if(selected){
selected.className = 'slider-list__item';
}
let item = this.items[idx];
if(item){
item.className = 'slider-list__item--selected';
}
const detail = {index: idx}
const event = new CustomEvent('slide', {bubbles:true, detail})
this.container.dispatchEvent(event)
}
slideNext(){
const currentIdx = this.getSelectedItemIndex();
const nextIdx = (currentIdx + 1) % this.items.length;
this.slideTo(nextIdx);
}
slidePrevious(){
const currentIdx = this.getSelectedItemIndex();
const previousIdx = (this.items.length + currentIdx - 1) % this.items.length;
this.slideTo(previousIdx);
}
addEventListener(type, handler){
this.container.addEventListener(type, handler);
}
start(){
this.stop();
this._timer = setInterval(()=>this.slideNext(), this.cycle);
}
stop(){
clearInterval(this._timer);
}
}
const pluginController = {
render(images){//随着图片数量的增加,小圆点元素也需要增加
return `
<div class="slide-list__control">
${images.map((image, i) => `
<span class="slide-list__control-buttons${i===0?'--selected':''}"></span>
`).join('')}
</div>
`.trim();
},
action(slider){
const controller = slider.container.querySelector('.slide-list__control');
if(controller){
const buttons = controller.querySelectorAll('.slide-list__control-buttons, .slide-list__control-buttons--selected');
controller.addEventListener('mouseover', evt => {
const idx = Array.from(buttons).indexOf(evt.target);
if(idx >= 0){
slider.slideTo(idx);
slider.stop();
}
});
controller.addEventListener('mouseout', evt => {
slider.start();
});
slider.addEventListener('slide', evt => {
const idx = evt.detail.index
const selected = controller.querySelector('.slide-list__control-buttons--selected');
if(selected) selected.className = 'slide-list__control-buttons';
buttons[idx].className = 'slide-list__control-buttons--selected';
});
}
}
};
const pluginPrevious = {
render(){
return `<a class="slide-list__previous"></a>`;
},
action(slider){
const previous = slider.container.querySelector('.slide-list__previous');
if(previous){
previous.addEventListener('click', evt => {
slider.stop();
slider.slidePrevious();
slider.start();
evt.preventDefault();
});
}
}
};
const pluginNext = {
render(){
return `<a class="slide-list__next"></a>`;
},
action(slider){
const previous = slider.container.querySelector('.slide-list__next');
if(previous){
previous.addEventListener('click', evt => {
slider.stop();
slider.slideNext();
slider.start();
evt.preventDefault();
});
}
}
};
const slider = new Slider('my-slider', {images: ['https://p5.ssl.qhimg.com/t0119c74624763dd070.png',
'https://p4.ssl.qhimg.com/t01adbe3351db853eb3.jpg',
'https://p2.ssl.qhimg.com/t01645cd5ba0c3b60cb.jpg',
'https://p4.ssl.qhimg.com/t01331ac159b58f5478.jpg'], cycle:3000});
slider.registerPlugins(pluginController, pluginPrevious, pluginNext);
slider.start();
每个插件都被构造成一个对象。每个对象中都有一个render方法,负责渲染各自的HTML。initialize方法则负责注册各自的用户事件。
方法四:设计组件框架
html
<div id="my-slider" class="slider-list"></div>
css
#my-slider{
position: relative;
width: 790px;
height: 340px;
}
.slider-list ul{
list-style-type:none;
position: relative;
width: 100%;
height: 100%;
padding: 0;
margin: 0;
}
.slider-list__item,
.slider-list__item--selected{
position: absolute;
transition: opacity 1s;
opacity: 0;
text-align: center;
}
.slider-list__item--selected{
transition: opacity 1s;
opacity: 1;
}
.slide-list__control{
position: relative;
display: table;
background-color: rgba(255, 255, 255, 0.5);
padding: 5px;
border-radius: 12px;
bottom: 30px;
margin: auto;
}
.slide-list__next,
.slide-list__previous{
display: inline-block;
position: absolute;
top: 50%;
margin-top: -25px;
width: 30px;
height:50px;
text-align: center;
font-size: 24px;
line-height: 50px;
overflow: hidden;
border: none;
background: transparent;
color: white;
background: rgba(0,0,0,0.2);
cursor: pointer;
opacity: 0;
transition: opacity .5s;
}
.slide-list__previous {
left: 0;
}
.slide-list__next {
right: 0;
}
#my-slider:hover .slide-list__previous {
opacity: 1;
}
#my-slider:hover .slide-list__next {
opacity: 1;
}
.slide-list__previous:after {
content: '<';
}
.slide-list__next:after {
content: '>';
}
.slide-list__control-buttons,
.slide-list__control-buttons--selected{
display: inline-block;
width: 15px;
height: 15px;
border-radius: 50%;
margin: 0 5px;
background-color: white;
cursor: pointer;
}
.slide-list__control-buttons--selected {
background-color: red;
}
JS
class Component{
constructor(id, opts = {name, data:[]}){
this.container = document.getElementById(id);
this.options = opts;
this.container.innerHTML = this.render(opts.data);
}
registerPlugins(...plugins){
plugins.forEach(plugin => {
const pluginContainer = document.createElement('div');
pluginContainer.className = `.${name}__plugin`;
pluginContainer.innerHTML = plugin.render(this.options.data);
this.container.appendChild(pluginContainer);
plugin.action(this);
});
}
render(data) {
/* abstract */
return ''
}
}
//Slider作为组件类继承自Component
class Slider extends Component{
constructor(id, opts = {name: 'slider-list', data:[], cycle: 3000}){
super(id, opts);
this.items = this.container.querySelectorAll('.slider-list__item, .slider-list__item--selected');
this.cycle = opts.cycle || 3000;
this.slideTo(0);
}
render(data){
const content = data.map(image => `
<li class="slider-list__item">
<img src="${image}"/>
</li>
`.trim());
return `<ul>${content.join('')}</ul>`;
}
getSelectedItem(){
const selected = this.container.querySelector('.slider-list__item--selected');
return selected
}
getSelectedItemIndex(){
return Array.from(this.items).indexOf(this.getSelectedItem());
}
slideTo(idx){
const selected = this.getSelectedItem();
if(selected){
selected.className = 'slider-list__item';
}
const item = this.items[idx];
if(item){
item.className = 'slider-list__item--selected';
}
const detail = {index: idx}
const event = new CustomEvent('slide', {bubbles:true, detail})
this.container.dispatchEvent(event)
}
slideNext(){
const currentIdx = this.getSelectedItemIndex();
const nextIdx = (currentIdx + 1) % this.items.length;
this.slideTo(nextIdx);
}
slidePrevious(){
const currentIdx = this.getSelectedItemIndex();
const previousIdx = (this.items.length + currentIdx - 1) % this.items.length;
this.slideTo(previousIdx);
}
addEventListener(type, handler){
this.container.addEventListener(type, handler);
}
start(){
this.stop();
this._timer = setInterval(()=>this.slideNext(), this.cycle);
}
stop(){
clearInterval(this._timer);
}
}
const pluginController = {
render(images){
return `
<div class="slide-list__control">
${images.map((image, i) => `
<span class="slide-list__control-buttons${i===0?'--selected':''}"></span>
`).join('')}
</div>
`.trim();
},
action(slider){
let controller = slider.container.querySelector('.slide-list__control');
if(controller){
let buttons = controller.querySelectorAll('.slide-list__control-buttons, .slide-list__control-buttons--selected');
controller.addEventListener('mouseover', evt=>{
var idx = Array.from(buttons).indexOf(evt.target);
if(idx >= 0){
slider.slideTo(idx);
slider.stop();
}
});
controller.addEventListener('mouseout', evt=>{
slider.start();
});
slider.addEventListener('slide', evt => {
const idx = evt.detail.index;
let selected = controller.querySelector('.slide-list__control-buttons--selected');
if(selected) selected.className = 'slide-list__control-buttons';
buttons[idx].className = 'slide-list__control-buttons--selected';
});
}
}
};
const pluginPrevious = {
render(){
return `<a class="slide-list__previous"></a>`;
},
action(slider){
let previous = slider.container.querySelector('.slide-list__previous');
if(previous){
previous.addEventListener('click', evt => {
slider.stop();
slider.slidePrevious();
slider.start();
evt.preventDefault();
});
}
}
};
const pluginNext = {
render(){
return `<a class="slide-list__next"></a>`;
},
action(slider){
let previous = slider.container.querySelector('.slide-list__next');
if(previous){
previous.addEventListener('click', evt => {
slider.stop();
slider.slideNext();
slider.start();
evt.preventDefault();
});
}
}
};
const slider = new Slider('my-slider', {name: 'slide-list', data: ['https://p5.ssl.qhimg.com/t0119c74624763dd070.png',
'https://p4.ssl.qhimg.com/t01adbe3351db853eb3.jpg',
'https://p2.ssl.qhimg.com/t01645cd5ba0c3b60cb.jpg',
'https://p4.ssl.qhimg.com/t01331ac159b58f5478.jpg'], cycle:3000});
slider.registerPlugins(pluginController, pluginPrevious, pluginNext);
slider.start();
一个组件Component包含一个API: static name--静态属性,表示这个组件的名称 contructor({container,data,parent})--组件构造函数 registerSubComponent(...Comps)--给当前组件注册子组件 render(data)--渲染HTML模板
后续的话:
写基本的版本,一步步地迭代
行为:控制流
虽然目前不太可能用原生的js一步步设计组件,vue、react框架有自己的组件模式,但还是要理解自己设计组件的思路
用原生的js实现组件框架
组件设计的原则:封装性、正确性、扩展性、复用性
实现组件的步骤:结构设计、展示效果、行为设计
过程抽象:用来处理局部细节控制的一些方法
函数式编程思想
过程抽象:为了能够让“只执行一次”的需求覆盖不同的事件处理,我们可以将这个需求剥离出来
常用高阶函数:
截留函数throttle
防抖函数debounce
comsumer/
isIterative:可复用 开发效率高 线程安全
幂等性:在任何一个时间点,在任何一个事件下它的结果都是相等的,
提示某个函数过时:
depracation.anounce.js
import {foo,bar} from 'lib'
function de
编程范式:命令式与声明式
过程抽象 HOF 装饰器 命令式 声明式
可维护性 可抽象性 可扩展性
回调函数是否会被GC回收?
大量使用闭包会导致内存泄露
日历 菜单组件 可以看组件库