5 - watch 全家桶

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// 你的答案

`

const count = ref(0)

/**

• Challenge 1: Watch once
• Make sure the watch callback only triggers once */ watch(count, () => { console.log("Only triggered once") },{once:true})

count.value = 1 setTimeout(() => count.value = 2)

/**

• Challenge 2: Watch object
• Make sure the watch callback is triggered */ const state = ref({ count: 0, })

watch(()=>state.value.count, () => { console.log("The state.count updated") })

state.value.count = 2

/**

• Challenge 3: Callback Flush Timing
• Make sure visited the updated eleRef */

const eleRef = ref() const age = ref(2) watch(age, () => { console.log(eleRef.value) },{flush:'post'}) age.value = 18

`