vuejs怎么watch对象里某个属性的变化

Question

vuejs怎么watch对象里某个属性的变化

Answer 1

用计算属性，返回值是这个列表值相加

computed: { countTotal: function () { let total = 0; this.items.forEach(function (item) { total += item.count }) return total } }

监听用 watch选项

watch: { items: { handler: function () {}, deep: true } }

对象要深复制，默认是浅复制

Answer 2

<pre t="code" l="js">new Vue({
data: {
name: 'sigma'
},
watch:{
name: function( val ){
console.log( 'name has been changed:', val );
}
}
})

Answer 3