execute a getAll method in an interval timer. This getAll method will read an interface using axios loop. Once the interface data changes, the new data will be written into vue.count. What I want to achieve now is that once the vue.count changes, the alert pop-up box and the audio tag play the sound, but I find that this has no effect. What is the reason? Why are old and new always the same?
watch you deserve
because you vue.old=vue.count these two are always equal, and you compare them later, you can use watch to implement this scenario, or
do not assign a value
if(vue.count===vue.old){
}else{
alert('new message')
}you can refer to this way of writing
new Vue({
el: "-sharpapp",
data() {
return {
count: ''
}
},
methods: {
getAll() {
return new Promise((resolve, reject) => {
axios.get('../json/menu.json').then(res => {
resolve(res.data)
})
})
}
},
watch: {
count: function () {
alert('')
}
},
mounted() {
let that = this;
setInterval(async () => {
that.count = await that.getAll()
}, 5000);
}
})use watch to listen on count
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