5.1、装饰器（代码）

1、typescript

class Circle {
  draw() {
    console.log('画一个⭕️')
  }
}
class Decorator {
  private circle: Circle;
  constructor(circle: Circle) {
    this.circle = circle;
  }
  draw() {
    this.circle.draw()
    this.drawLine()
  }
  drawLine() {
    console.log('画一个直线')
  }
}
const circle = new Circle()
const decorator = new Decorator(circle)
decorator.draw()

2、前端里面装饰器（@）

function mixins(...list) {
  return function (target) {
    Object.assign(target.prototype, ...list)
  }
}
const Foo = {
  foo() {
    console.log('foo')
  }
}
interface obj {
  [key: string]: any
}
@mixins(Foo)
class Myclass {
}
var obj: obj = new Myclass()
obj.foo()

3、装饰器方法readonly

function readonly(target, name, descriptor) {
  descriptor.writable = false
  return descriptor
}
class Person {
  first: string;
  last: string;
  constructor() {
    this.first = 'Kip'
    this.last = 'song'
  }
  @readonly
  name() {
    console.log(`${this.first} ${this.last}`)
  }
}
var p = new Person()
console.log(p.name())
p.name = function () {
  alert(100)
}
p.name()    // 还是之前的name方法

4、装饰log日志

function log(target, name, descriptor) {
  let oldValue = descriptor.value
  descriptor.value = function () {
    console.log(`操作了 ${name} 方法`, arguments)
    return oldValue.apply(this, arguments)
  }
  return descriptor
}
class MyMath {
  @log
  add(a: number, b: number) {
    return a + b
  }
}
const math = new MyMath()
math.add(1, 2)

5、装饰一下小程序代码（字面意思哦）

export default {
  /**
   * @author Kip song
   * @param {*} params
   * @param {*} method
   */
  baseOptions(params, method = "GET") {
    return new Promise(function (resolve, reject) {
      let { url, data } = params
      let contentType = "application/json"
      contentType = params.contentType || contentType
      const option = {
        url: url.indexOf("http") !== -1 ? url : config.url + url,
        data: data,
        method: method,
        header: { 'content-type': contentType, 'Wx-Token': getToken() },
        success(res) {
          if (res.statusCode === HTTP_STATUS.NOT_FOUND) {
            wx.hideLoading()
            wx.showToast({
              title: '服务器找不到您所请求的文件或脚本！',
              icon: 'none',
              duration: 1500
            })
          } else if (res.statusCode === HTTP_STATUS.BAD_GATEWAY) {
            wx.hideLoading()
            wx.showToast({
              title: '服务端异常，请稍后尝试！',
              icon: 'none',
              duration: 1500
            })
          } else if (res.statusCode === HTTP_STATUS.FORBIDDEN) {
            wx.hideLoading()
            wx.showToast({
              title: '没有权限访问！',
              icon: 'none',
              duration: 1500
            })
          } else if (res.statusCode === HTTP_STATUS.SUCCESS) {
            let _data = res.data
            if (_data.code == 0) {
              resolve(_data)
            } else {
              wx.showToast({
                title: _data.msg || _data.message || `错误状态${_data.code}`,
                icon: 'none',
                duration: 1500
              })
            }
          } else {
            wx.hideLoading()
            wx.showToast({
              title: '网络出现故障，请重新尝试！',
              icon: 'none',
              duration: 1500
            })
          }
        },
        fail(e) {
          wx.showToast({
            title: '网络超时，请重新操作！',
            icon: 'none',
            duration: 1500
          })
        }
      }
      wx.request(option)
    })
  },
  /**
     * GET请求
     * @param url 请求路径
     * @param data 参数
     */
  get(url, data) {
    let option = { url, data }
    return this.baseOptions(option, "GET")
  },
  /**
   * POST请求
   * @param url 请求路径
   * @param data 参数
   */
  post(url, data) {
    let option = { url, data }
    return this.baseOptions(option, "POST")
  },
  /**
   * PUT请求
   * @param url 请求路径
   * @param data 参数
   */
  put(url, data) {
    let option = { url, data }
    return this.baseOptions(option, "PUT")
  },
  /**
   * DELETE请求
   * @param url 请求路径
   * @param data 参数
   */
  delete(url, data) {
    let option = { url, data }
    return this.baseOptions(option, "DELETE")
  }
}