HarmonyOS鸿蒙Next中@Watch可以观察到@Consume装饰的状态变量更改吗

可以观察的，尝试如下代码。

@Component

struct CompD {

  @Consume @Watch('onChange') selectedDate: Date;

  onChange() {
    console.info("值改变了！！！");
  }

  build() {

    Column() {

      Button(`child increase the day by 1`)
        .onClick(() => {
          this.selectedDate.setDate(this.selectedDate.getDate() + 1)
        })

      Button('child update the new date')
        .margin(10)
        .onClick(() => {
          this.selectedDate = new Date('2023-09-09')
        })

      DatePicker({
        start: new Date('1970-1-1'),
        end: new Date('2100-1-1'),
        selected: this.selectedDate
      })
    }
  }
}

@Component

struct CompA {

  @Provide selectedDate: Date = new Date('2021-08-08')

  build() {

    Column() {

      Button('parent increase the day by 1')
        .margin(10)
        .onClick(() => {
          this.selectedDate.setDate(this.selectedDate.getDate() + 1)
        })

      Button('parent update the new date')
        .margin(10)
        .onClick(() => {
          this.selectedDate = new Date('2023-07-07')
        })

      DatePicker({
        start: new Date('1970-1-1'),
        end: new Date('2100-1-1'),
        selected: this.selectedDate
      })

      CompD()
    }
  }
}