V - memo new instructions

v-memod will remember a subtree of templates,It can be used on both span> elements and components.This command accepts a fixed-length array as a dependency value for [memory comparison].If every value in the array is the same as when it was last rendered, the update of the entire subtree is skipped.Even the VNode creation of a virtual DOM will be skipped because the memoized copy of the subtree can be reused.So the rendering speed will be very fast.It is important to note that: correctly declare the memory array.It is the developer's responsibility to specify the correct dependency array to avoid necessary updates being skipped.<li v-for="item in listArr" :key="item.id" v-memo="['valueA','valueB']">{{ item.name }}</li>v-memod's directive is used less, its role is to : cache part of the data in the template.Create it once and never update it again.That is to say, memory is exchanged for time.