(isUndef(target) ||isPrimitive(target)) ) {warn(`Cannot set reactive property on undefined, null, or primitive value:${(target: any)}`) }// 2.如果是数组 Vue.set(array,1,100); 调用我们重写的splice方法 (这样可以更新视图)if(Array.isArray(target) &&isValidArrayIndex(key)) { target.leng...
Version 3.2.31 Reproduction link sfc.vuejs.org/ Steps to reproduce Click the 'unmount app' button The error message will show in the Developer Tools Console TypeError: Cannot read properties of null (reading 'nextSibling') What is expect...
About 90% of the API of Vue 2.X is the same with the API of Vue 1.X and there is no change in the core concept. This is going to be a long tutorial because we will like to offer very detailed explanations and include a lot of examples. You don?t have to read from top to b...
render包含了挂载和卸载,如果你传入的vnode是null,就会走组件卸载的逻辑,如果是有效vnode,那就是正常的根组件挂载 constrender:RootRenderFunction=(vnode,container)=>{if(vnode==null){// 传入vnode为null,并且已有挂载的根vnode,表示要对根组件进行卸载操作if(container._vnode){unmount(container._vnode,null,nul...
接受一个内部值并返回一个响应式且可变的 ref 对象。ref 对象仅有一个.valueproperty,指向该内部值。 案例 我们这样操作是无法改变message 的值 应为message 不是响应式的无法被vue 跟踪要改成ref <template>change{{ message }}</template>let message: string="我是message"const changeMsg=()=>{ message...
varactiveInstance=null;varisUpdatingChildComponent=false;//设置当前的Vue实例 其返还结果为恢复上一个Vue实例,类似栈的思想来进行树状结构的构建functionsetActiveInstance(vm){varprevActiveInstance=activeInstance;activeInstance=vm;returnfunction(){activeInstance=prevActiveInstance;}}//方法主要用来初始化生命周期相关...
When this happens, you cannot drag/drop correctly and get a throw error in the onDragStart event: Cannot read properties of null (reading 'element') codesandbox.io link https://codesandbox.io/s/bold-pike-xrddv Step by step scenario Take something like this for App.vue Id First Name...
{currentRenderingInstance=null;}// if the returned array contains only a single node, allow itif(Array.isArray(vnode)&&vnode.length===1){vnode=vnode[0];}// return empty vnode in case the render function errored outif(!(vnodeinstanceofVNode)){if(Array.isArray(vnode)){warn('Multiple ...
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commits: null, truncate(v) { const newline = v.indexOf('\n') return newline > 0 ? v.slice(0, newline) : v }, formatDate(v) { return v.replace(/T|Z/g, ' ') }, fetchData() { fetch(`${API_URL}${this.currentBranch}`) ...