<script setup>
    import {
        ref,
        computed,
        watch,
        watchEffect,
        effectScope,
        getCurrentScope,
        onScopeDispose
    } from 'vue'

    const counter = ref(2)

    // 定义第一个侦听管家
    const scope = effectScope()
    scope.run(() => {
        const doubled = computed(() => counter.value * 2)
        watch(doubled, () => console.log(doubled.value))
        watchEffect(() => console.log('Count: ', doubled.value))
    })
    //scope.stop()  // 调用它，可以取消scope内的侦听。执行这个不会触发onScopeDispose事件

    //  定义第二个侦听管家
    const scope2 = effectScope()
    scope2.run(() => {
        const doubled2 = computed(() => counter.value * 3)
        watch(doubled2, () => console.log(doubled2.value))
        watchEffect(() => console.log('Count: ', doubled2.value))
    })
    //scope2.stop() // 调用它，可以取消scope2内的侦听。执行这个不会触发onScopeDispose事件

    // 获取当前侦听实例
    const allScope = getCurrentScope()
    // 执行 allScope.stop()时会触发 onScopeDispose 事件
    // 当前页面或组件注销时会触发 onScopeDispose 事件
    onScopeDispose(() => {
        console.log('已停止所有侦听');
        // to do...
    })
  
    // 5秒后停止所有侦听，此时会触发 onScopeDispose 事件
    setTimeout(() => {
        allScope.stop()
    }, 5000)
</script>