Match-id-2f02df2d3c1d025e6670522bf52a3cf7b1bad90d

libs/horizon/src/renderer/diff/nodeDiffComparator.ts

@@ -1,7 +1,7 @@
 import type { VNode } from '../Types';
 import { FlagUtils } from '../vnode/VNodeFlags';
 import { TYPE_COMMON_ELEMENT, TYPE_FRAGMENT, TYPE_PORTAL } from '../../external/JSXElementType';
-import { DomText, DomPortal, Fragment } from '../vnode/VNodeTags';
+import { DomText, DomPortal, Fragment, DomComponent } from '../vnode/VNodeTags';
 import {updateVNode, createVNode, createVNodeFromElement, updateVNodePath} from '../vnode/VNodeCreator';
 import {
   isSameType,
@@ -320,8 +320,13 @@ function diffArrayNodes(
   // 3. 新节点已经处理完成
   if (leftIdx === rightIdx) {
     if (isComparing) {
+      if (firstChild && parentNode.tag === DomComponent && newChildren.length === 0) {
+        FlagUtils.markClear(parentNode);
+        parentNode.clearChild = firstChild;
+      } else {
         deleteVNodes(parentNode, oldNode, rightEndOldNode);
       }
+    }
 
     if (rightNewNode) {
       appendNode(rightNewNode);

libs/horizon/src/renderer/submit/LifeCycleHandler.ts

@@ -17,7 +17,7 @@ import {
   SuspenseComponent,
   MemoComponent,
 } from '../vnode/VNodeTags';
-import { FlagUtils, ResetText } from '../vnode/VNodeFlags';
+import { FlagUtils, ResetText, Clear } from '../vnode/VNodeFlags';
 import { mergeDefaultProps } from '../render/LazyComponent';
 import {
   submitDomUpdate,
@@ -307,6 +307,42 @@ function unmountDomComponents(vNode: VNode): void {
   });
 }
 
+function submitClear(vNode: VNode): void {
+  const realNode = vNode.realNode;
+  const cloneDom = realNode.cloneNode(false); // 复制节点后horizon添加给dom的属性未能复制
+  // 真实 dom 获取的keys只包含新增的属性
+  // 比如真实 dom 拿到的 keys 一般只有两个 horizon 自定义属性
+  // 但考虑到用户可能自定义其他属性，所以采用遍历赋值的方式
+  const customizeKeys = Object.keys(realNode);
+  const keyLength = customizeKeys.length;
+  for(let i = 0; i < keyLength; i++) {
+    const key = customizeKeys[i];
+    // 测试代码 mock 实例的全部可遍历属性都会被Object.keys方法读取到
+    // children 属性被复制意味着复制了子节点，因此要排除
+    if (key !== 'children') {
+      cloneDom[key] = realNode[key]; // 复制cloneNode未能复制的属性
+    }
+  }
+
+  const parentObj = findDomParent(vNode);
+  const currentParent = parentObj.parentDom;
+  let clearChild = vNode.clearChild as VNode; // 上次渲染的child保存在clearChild属性中
+  // 卸载 clearChild 和 它的兄弟节点
+  while(clearChild) {
+    // 卸载子vNode，递归遍历子vNode
+    unmountNestedVNodes(clearChild);
+    clearVNode(clearChild);
+    clearChild = clearChild.next as VNode;
+  }
+  
+  // 在所有子项都卸载后，删除dom树中的节点
+  removeChildDom(currentParent, vNode.realNode);
+  currentParent.append(cloneDom);
+  vNode.realNode = cloneDom;
+  FlagUtils.removeFlag(vNode, Clear);
+  vNode.clearChild = null;
+}
+
 function submitDeletion(vNode: VNode): void {
   // 遍历所有子节点：删除dom节点，detach ref 和 调用componentWillUnmount()
   unmountDomComponents(vNode);
@@ -353,6 +389,7 @@ export {
   submitResetTextContent,
   submitAddition,
   submitDeletion,
+  submitClear,
   submitUpdate,
   callAfterSubmitLifeCycles,
   attachRef,

libs/horizon/src/renderer/submit/Submit.ts

@@ -9,7 +9,7 @@ import {
   attachRef,
   callAfterSubmitLifeCycles,
   callBeforeSubmitLifeCycles, submitDeletion, submitAddition,
-  submitResetTextContent, submitUpdate, detachRef,
+  submitResetTextContent, submitUpdate, detachRef, submitClear,
 } from './LifeCycleHandler';
 import {tryRenderRoot, setProcessing} from '../TreeBuilder';
 import {
@@ -121,7 +121,7 @@ function submit(dirtyNodes: Array<VNode>) {
         }
       }
 
-      const {Addition, Update, Deletion} = node.flags;
+      const {Addition, Update, Deletion, Clear} = node.flags;
       if (Addition && Update) {
         // Addition
         submitAddition(node);
@@ -138,6 +138,9 @@ function submit(dirtyNodes: Array<VNode>) {
         } else if (Deletion) {
           submitDeletion(node);
         }
+        if (Clear) {
+          submitClear(node);
+        }
       }
     } catch (error) {
       throwIfTrue(node === null, 'Should be working on an effect.');

libs/horizon/src/renderer/vnode/VNode.ts

@@ -60,8 +60,9 @@ export class VNode {
     Interrupted?: boolean;
     ShouldCapture?: boolean;
     ForceUpdate?: boolean;
+    Clear?: boolean;
   } = {};
-
+  clearChild: VNode | null = null;
   // one tree相关属性
   isCreated: boolean = true;
   oldHooks: Array<Hook<any, any>> = []; // 保存上一次执行的hook

libs/horizon/src/renderer/vnode/VNodeFlags.ts

@@ -18,8 +18,9 @@ export const Interrupted = 'Interrupted';
 export const ShouldCapture = 'ShouldCapture';
 // For suspense
 export const ForceUpdate = 'ForceUpdate';
+export const Clear = 'Clear';
 
-const FlagArr = [Addition, Update, Deletion, ResetText, Callback,
+const FlagArr = [Addition, Update, Deletion, Clear, ResetText, Callback,
   DidCapture, Ref, Snapshot, Interrupted, ShouldCapture, ForceUpdate];
 
 const LifecycleEffectArr = [Update, Callback, Ref, Snapshot];
@@ -90,5 +91,9 @@ export class FlagUtils {
   static markForceUpdate(node: VNode) {
     node.flags.ForceUpdate = true;
   }
+
+  static markClear(node: VNode) {
+    node.flags.Clear = true;
+  }
 }