怎样用h5做网站,prozac,快速做网站关键词排名,太平洋建设集团有限公司网站watch的属性值
handler:回调函数, 即监听到变化时应该执行的函数#xff0c;可以是单独的函数或带有 immediate 和 deep 属性的对象watch: {someProperty: function(newVal, oldVal) {// 处理逻辑}}deep: 其值是true或false, 当属性值是对象或数组时#xff0c;深度观察会监…watch的属性值
handler:回调函数, 即监听到变化时应该执行的函数可以是单独的函数或带有 immediate 和 deep 属性的对象watch: {someProperty: function(newVal, oldVal) {// 处理逻辑}}deep: 其值是true或false, 当属性值是对象或数组时深度观察会监控对象内部所有层级的变化。watch: {someObject: {handler(newVal, oldVal) {// 处理逻辑},deep: true}}immediate: 值是true或false,首次绑定时立即执行回调函数watch: {someProperty: {handler(newVal, oldVal) {// 处理逻辑},immediate: true}}vue2写法:
//基本用法watch:{avatar(navl,oval){console.log(navl,navl);console.log(oval,oval);}},
//深度监听
watch: {user: {handler(nval,oval) {console.log(nval,oval);},deep: true,}},
//立即执行
watch: {user: {handler(nval,oval) {console.log(nval,oval);},immediate: true}},
//观察数组中特定项的变化watch: {user[0]: function(newVal, oldVal) {console.log(user[0] changed from, oldVal, to, newVal);}
//监听多个数据源watch: {property1(newVal, oldVal) {console.log(property1 changed from, oldVal, to, newVal);},property2(newVal, oldVal) {console.log(property2 changed from, oldVal, to, newVal);}}
vue3写法
import { watch } from vue;
//基本用法
watch(avatar, (newVal, oldVal) {console.log(avatarchanged from, oldVal, to, newVal);
});//深度管察
watch(() user,(nval,oval) {console.log(val, oval)},{ deep:true }
)//立即执行
watch(() user,(nval,oval) {console.log(val, oval)},{ immediate: true }
)//使用回调函数对象
watch(someProperty,{handler(newVal, oldVal) {console.log(someProperty changed from, oldVal, to, newVal);},immediate: true,deep: true});
