HarmonyOS 注解功能

可以参考自定义装饰器，ArkTS支持自定义装饰器，比如支持如下的装饰器

export function MyDescriptor(target: Object, key: string, descriptor: PropertyDescriptor) {
  const originalMethod: Function = descriptor.value
  descriptor.value = (...args: Object[]) => {
    console.log(`Calling ${target.constructor.name} method ${key} with argument: ${args}`)
    const result: Object = originalMethod(...args)
    console.log(`Method ${key} returned: ${result}`)
    return result
  }
  return descriptor
}
// 使用
@MyDescriptor
demo() {
  console.log('ccc')
  return 'cccc'
}

import { MyDescriptor } from '../common/decorators'

@Entry
@Component
struct Index{
  @State message: string = 'Hello World';
  aboutToAppear() {
    this.demo()
  }

  build() {
    Flex() {
    }
    .backgroundColor(Color.Green)
    .constraintSize({
      minWidth: 100,
      maxWidth: 200,
      minHeight: 0,
      maxHeight: 200
    })
    .height('100%')
  }

  @MyDescriptor
  demo() {
    console.log('ccc')
    return 'cccc'
  }
}

export function MyDescriptor(target: Object, key: string, descriptor: PropertyDescriptor) {
  const originalMethod: Function = descriptor.value
  descriptor.value = (...args: Object[]) => {
    console.log(`Calling ${target.constructor.name} method ${key} with argument: ${args}`)
    const result: Object = originalMethod(...args)
    console.log(`Method ${key} returned: ${result}`)
    return result
  }
  return descriptor
}