(四)js前端开发中设计模式之工厂方法模式

工厂方法模式,通过对产品类的抽象，使其创建业务主要用于负责创建多类产品的实例

const Java = function (content) {this.content = content;(function () {let oDiv = document.createElement('div')oDiv.innerHTML = contentoDiv.style.color = 'green'document.getElementById('container').appendChild(oDiv)})()
}const Php = function (content) {this.content = content;(function () {let oDiv = document.createElement('div')oDiv.innerHTML = contentoDiv.style.color = 'red'document.getElementById('container').appendChild(oDiv)})()
}const JavaScript = function (content) {this.content = content;(function () {let oDiv = document.createElement('div')oDiv.innerHTML = contentoDiv.style.color = 'pink'document.getElementById('container').appendChild(oDiv)})()
}

简单工厂模式，扩展的话需要改动两个地方，一个是工厂类，一个是具体产品类

function JobFactory(type, content) {switch (type) {case 'java':return new Java(content)breakcase 'javascript':return new JavaScript(content)break}
}JobFactory('java', 'Java 培训哪家强1111')

安全模式实例

var Demo = function () {}
Demo.prototype.show = function () {console.log('show')
}//正常使用
let d1 = new Demo()
d1.show() //show//非正常使用
// let d2 = Demo()
// d2.show() //报错//改造上面的 democonst Demo2 = function () {// if (this instanceof Demo2) {// return this// } else {// return new Demo2()// }console.log('🚀 ~ Demo2 ~ this:', this)if (!(this instanceof Demo2)) {console.log('🚀 ~ Demo2 ~ new Demo2():', new Demo2())return new Demo2()}
}Demo2.prototype.show = function () {console.log('show 999')
}let d2 = Demo2()
d2.show() //报错

工厂方法模式，扩展的话只需要改动工厂类

const Factory = function (type, content) {if (this instanceof Factory) {return new this[type](content)} else {return new Factory(type, content)}
}Factory.prototype = {//注意方法这里不能简写需要：functionJava: function (content) {//注意这里不能加thisthis.content = contentconsole.log('🚀 ~ content11111:', content);(function () {let oDiv = document.createElement('div')oDiv.innerHTML = contentoDiv.style.color = 'green'document.getElementById('container').appendChild(oDiv)})()},JavaScript: function (content) {this.content = content;(function () {let oDiv = document.createElement('div')oDiv.innerHTML = contentoDiv.style.color = 'red'document.getElementById('container').appendChild(oDiv)})()},UIEvent: function (content) {this.content = content;(function () {let oDiv = document.createElement('div')oDiv.innerHTML = contentoDiv.style.color = 'pink'document.getElementById('container').appendChild(oDiv)})()},Php: function (content) {this.content = content;(function () {let oDiv = document.createElement('div')oDiv.innerHTML = contentoDiv.style.color = 'blue'document.getElementById('container').appendChild(oDiv)})()}
}

实现

const data = [{type: 'Java',content: 'Java 培训哪家强'},{type: 'JavaScript',content: 'JavaScript 培训哪家强'},{type: 'Php',content: 'PHP 培训哪家强'},{type: 'UIEvent',content: 'UIEvent 培训哪家强'}
]//创建实例
for (let i = 0; i < data.length; i++) {Factory(data[i].type, data[i].content)
}