扬州广陵区建设局网站,广州 环保 凡人网站建设,佳木斯城乡建设局网站,门户网站设计欣赏发现nextTick必须放在修改一个响应式数据之后#xff0c;才会在onUpdated之后被调用#xff0c;如果nextTick是放在所有对响应式数据修改之前#xff0c;则nextTick里面的回调函数会在onBeforeUpdate方法执行前就被调用了。可是nextTick必须等到onUpdated执行完成之后执行才会在onUpdated之后被调用如果nextTick是放在所有对响应式数据修改之前则nextTick里面的回调函数会在onBeforeUpdate方法执行前就被调用了。可是nextTick必须等到onUpdated执行完成之后执行才能拿到渲染得到的dom下面发请求的时候是没有使用async的(Promise的语法糖)它里面的then函数对serverRef的修改会再一次触发组件重新渲染也就是onBeforeUpdate和onUpdated又被回调了一次也就是说下面的toggleColor这个方法触发了2次渲染。
---onBeforeMounted---
RefImpl {__v_isShallow: false, dep: undefined, __v_isRef: true, _rawValue: null, _value: null}
---mounted---
RefImpl {__v_isShallow: false, dep: undefined, __v_isRef: true, _rawValue: span, _value: span}
halo world
---onBeforeUpdate---
---onUpdated---
RefImpl {__v_isShallow: false, dep: undefined, __v_isRef: true, _rawValue: button, _value: button}
nextTick1
res ojbk
---onBeforeUpdate---
---onUpdated---
nextTick2templatediv styledisplay: flex;ul classul-listli v-fori in num :idlii {{ i }}/li/uldiv classdiv-descinput typetext v-modelnbutton clickhandleClick修改num/buttonbrbrbutton clicktoggleColor切换span颜色/buttonspan refspanRef :style{color:colorRef}span/span*{{ serverResp }}*button v-ifisShow refbtnRefdd/button/div/div/templatescript langts setupimport { ref,reactive,onBeforeMount,onMounted,onBeforeUpdate,onUpdated,nextTick,getCurrentInstance } from vueconst { proxy } getCurrentInstance()let num ref(10)let n ref(10)const btnRef ref(null)let isShow ref(false)let serverResp ref()const spanRef ref(null)const handleClick () {num.value parseInt(n.value)}const colorRef ref()const toggleColor () {debuggerproxy.Request({url:http://localhost:8083/test}).then(res{debuggerconsole.log(res,res);serverResp.value resnextTick((){ // 要放在对响应式数据修改之后debuggerconsole.log(nextTick2);})})debuggerisShow.value truenextTick((){ // 要放在对至少一个响应式数据修改之后// 否则这里函数调用将拿不到btnRef,必须要等到onUpdated回调之后执行nextTick里面的回调才能拿到btnRefdebuggerconsole.log(btnRef); console.log(nextTick1);})if(colorRef.value red) {colorRef.value blue} else {colorRef.value red}num.value num.value - 1debuggerconsole.log(halo world);}onBeforeMount(() {console.log(---onBeforeMounted---)console.log(spanRef);})onMounted((){console.log(---mounted---)console.log(spanRef);spanRef.value.style.color cyan}) onBeforeUpdate((){debuggerconsole.log(---onBeforeUpdate---)})onUpdated((){debuggerconsole.log(---onUpdated---)})/scriptstyle langscss.ul-list {width: 100px;}.div-list { width: 300px;}
/style
