feat(module:tree): support virtual scroll (NG-ZORRO#4979)

close NG-ZORRO#4426 close NG-ZORRO#3808 close NG-ZORRO#3436 close NG-ZORRO#2680 close NG-ZORRO#1771

components/core/tree/nz-tree-base-node.ts

@@ -387,7 +387,6 @@ export class NzTreeNode {
 
   public update(): void {
     if (this.component) {
-      this.component.setClassMap();
       this.component.markForCheck();
     }
   }

components/core/tree/nz-tree-base-util.ts

@@ -46,6 +46,7 @@ export function flattenTreeData(treeNodeList: NzTreeNode[] = [], expandedKeys: N
       treeNode.isStart = [...(parent ? parent.isStart : []), index === 0];
       treeNode.isEnd = [...(parent ? parent.isEnd : []), index === list.length - 1];
       // Add FlattenDataNode into list
+      // TODO: only need data here.
       const flattenNode: FlattenNode = {
         parent,
         pos,

components/core/tree/nz-tree-base.definitions.ts

@@ -27,6 +27,5 @@ export interface NzFormatBeforeDropEvent {
 }
 
 export interface NzTreeNodeBaseComponent {
-  setClassMap(): void;
   markForCheck(): void;
 }

components/core/tree/nz-tree-base.service.ts

@@ -9,7 +9,8 @@
 import { Injectable } from '@angular/core';
 
 import { NzSafeAny } from 'ng-zorro-antd/core/types';
-import { FlattenNode, NzTreeNode, NzTreeNodeKey } from './nz-tree-base-node';
+import { BehaviorSubject } from 'rxjs';
+import { NzTreeNode, NzTreeNodeKey } from './nz-tree-base-node';
 import { flattenTreeData, isCheckDisabled, isInArray } from './nz-tree-base-util';
 import { NzFormatEmitEvent } from './nz-tree-base.definitions';
 
@@ -22,7 +23,7 @@ export class NzTreeBaseService {
   isMultiple: boolean = false;
   selectedNode: NzTreeNode;
   rootNodes: NzTreeNode[] = [];
-  flattenNodes: FlattenNode[] = [];
+  flattenNodes$ = new BehaviorSubject<NzTreeNode[]>([]);
   selectedNodeList: NzTreeNode[] = [];
   expandedNodeList: NzTreeNode[] = [];
   checkedNodeList: NzTreeNode[] = [];
@@ -42,7 +43,7 @@ export class NzTreeBaseService {
   }
 
   flattenTreeData(nzNodes: NzTreeNode[], expandedKeys: NzTreeNodeKey[] | true = []): void {
-    this.flattenNodes = flattenTreeData(nzNodes, expandedKeys);
+    this.flattenNodes$.next(flattenTreeData(nzNodes, expandedKeys).map(item => item.data));
   }
 
   getSelectedNode(): NzTreeNode | null {

components/tree/demo/customized-icon.ts

@@ -3,20 +3,11 @@ import { Component } from '@angular/core';
 @Component({
   selector: 'nz-demo-tree-customized-icon',
   template: `
-    <nz-tree [nzData]="nodes" nzShowIcon [nzExpandedIcon]="expandedIconTpl">
-      <ng-template #expandedIconTpl let-node>
-        <i nz-icon [nzType]="node.origin.icon" class="ant-tree-switcher-icon"></i>
-      </ng-template>
-    </nz-tree>
-    <nz-tree [nzData]="nodes" nzShowIcon [nzExpandedIcon]="mutiExpandedIconTpl">
-      <ng-template #mutiExpandedIconTpl let-node>
-        <i
-          *ngIf="!node.origin.isLeaf"
-          nz-icon
-          [nzType]="node.isExpanded ? 'folder-open' : 'folder'"
-          class="ant-tree-switcher-line-icon"
-        ></i>
-        <i *ngIf="node.origin.isLeaf" nz-icon nzType="file" class="ant-tree-switcher-line-icon"></i>
+    <nz-tree [nzData]="nodes" nzShowIcon></nz-tree>
+    <nz-tree [nzData]="nodes" nzShowIcon [nzExpandedIcon]="multiExpandedIconTpl">
+      <ng-template #multiExpandedIconTpl let-node let-origin="origin">
+        <i *ngIf="!origin.isLeaf" nz-icon [nzType]="node.isExpanded ? 'folder-open' : 'folder'" class="ant-tree-switcher-line-icon"></i>
+        <i *ngIf="origin.isLeaf" nz-icon nzType="file" class="ant-tree-switcher-line-icon"></i>
       </ng-template>
     </nz-tree>
   `

components/tree/demo/directory.md

@@ -7,8 +7,8 @@ title:
 
 ## zh-CN
 
-自定义目录树(使用 `nzTreeTemplate` 实现，支持右键)。
+使用 `nzTreeTemplate` 实现自定义目录结构，通过 `let-origin="origin"` 获得原始数据，`let-node` 获取当前节点状态。
 
 ## en-US
 
-Customize directory tree(with `nzTreeTemplate`, supported contextmenu).
+Customize directory tree with `nzTreeTemplate`, get data from `let-origin="origin"`, get node status from `let-node`.

components/tree/demo/directory.ts

@@ -12,7 +12,7 @@ import { NzContextMenuService, NzDropdownMenuComponent } from 'ng-zorro-antd/dro
       (nzDblClick)="openFolder($event)"
       [nzTreeTemplate]="nzTreeTemplate"
     ></nz-tree>
-    <ng-template #nzTreeTemplate let-node let-origin>
+    <ng-template #nzTreeTemplate let-node let-origin="origin">
       <span class="custom-node">
         <span *ngIf="!node.isLeaf" (contextmenu)="contextMenu($event, menu)">
           <i nz-icon [nzType]="node.isExpanded ? 'folder-open' : 'folder'" (click)="openFolder(node)"></i>
@@ -35,16 +35,12 @@ import { NzContextMenuService, NzDropdownMenuComponent } from 'ng-zorro-antd/dro
   `,
   styles: [
     `
-      :host ::ng-deep .ant-tree {
+      nz-tree {
         overflow: hidden;
         margin: 0 -24px;
         padding: 0 24px;
       }
 
-      :host ::ng-deep .ant-tree li {
-        padding: 4px 0 0 0;
-      }
-
       .custom-node {
         cursor: pointer;
         line-height: 24px;
@@ -70,8 +66,8 @@ import { NzContextMenuService, NzDropdownMenuComponent } from 'ng-zorro-antd/dro
   ]
 })
 export class NzDemoTreeDirectoryComponent {
-  // actived node
-  activedNode: NzTreeNode;
+  // activated node
+  activatedNode: NzTreeNode;
   nodes = [
     {
       title: 'parent 0',
@@ -94,7 +90,7 @@ export class NzDemoTreeDirectoryComponent {
     }
   ];
 
-  openFolder(data: NzTreeNode | Required<NzFormatEmitEvent>): void {
+  openFolder(data: NzTreeNode | NzFormatEmitEvent): void {
     // do something if u want
     if (data instanceof NzTreeNode) {
       data.isExpanded = !data.isExpanded;
@@ -107,7 +103,7 @@ export class NzDemoTreeDirectoryComponent {
   }
 
   activeNode(data: NzFormatEmitEvent): void {
-    this.activedNode = data.node!;
+    this.activatedNode = data.node!;
   }
 
   contextMenu($event: MouseEvent, menu: NzDropdownMenuComponent): void {

components/tree/demo/virtual-scroll.md

@@ -0,0 +1,14 @@
+---
+order: 8
+title:
+  zh-CN: 虚拟滚动
+  en-US: Virtual Scroll
+---
+
+## zh-CN
+
+设定 `nzVirtualHeight` 开启虚拟滚动。
+
+## en-US
+
+Set `nzVirtualHeight` to enable virtual scroll.

components/tree/demo/virtual-scroll.ts

@@ -0,0 +1,36 @@
+import { Component, OnInit } from '@angular/core';
+import { NzTreeNodeOptions } from 'ng-zorro-antd';
+
+@Component({
+  selector: 'nz-demo-tree-virtual-scroll',
+  template: ` <nz-tree [nzData]="nodes" nzBlockNode nzVirtualHeight="300px"></nz-tree> `
+})
+export class NzDemoTreeVirtualScrollComponent implements OnInit {
+  nodes: NzTreeNodeOptions[] = [];
+  ngOnInit(): void {
+    const dig = (path = '0', level = 3) => {
+      const list = [];
+      for (let i = 0; i < 10; i += 1) {
+        const key = `${path}-${i}`;
+        const treeNode: NzTreeNodeOptions = {
+          title: key,
+          key,
+          expanded: true,
+          children: [],
+          isLeaf: false
+        };
+
+        if (level > 0) {
+          treeNode.children = dig(key, level - 1);
+        } else {
+          treeNode.isLeaf = true;
+        }
+
+        list.push(treeNode);
+      }
+      return list;
+    };
+
+    this.nodes = dig();
+  }
+}

components/tree/doc/index.en-US.md

@@ -38,6 +38,10 @@ import { NzTreeModule } from 'ng-zorro-antd/tree';
 | `[nzSearchValue]` | Filter (highlight) treeNodes (see demo `Searchable`), two-way binding | `string` | `null` |
 | `[nzSearchFunc]` | Custom matching method, used with nzSearchValue | `(node: NzTreeNodeOptions) => boolean` | `null` |
 | `[nzBeforeDrop]` | Drop before the second check, allowing the user to decide whether to allow placement | `(confirm: NzFormatBeforeDropEvent) => Observable<boolean>` | - |
+| `[nzVirtualHeight]` | The height of virtual scroll | `string` | `-` |
+| `[nzVirtualItemSize]` | The size of the items in the list, same as [cdk itemSize](https://material.angular.io/cdk/scrolling/api) | `number` | `0` |
+| `[nzVirtualMaxBufferPx]` | The number of pixels worth of buffer to render for when rendering new items, same as [cdk maxBufferPx](https://material.angular.io/cdk/scrolling/api) | `number` | `200` |
+| `[nzVirtualMinBufferPx]` | The minimum amount of buffer rendered beyond the viewport (in pixels),same as [cdk minBufferPx](https://material.angular.io/cdk/scrolling/api) | `number` | `100` |
 | `(nzClick)` | Callback function for when the user clicks a treeNode | `EventEmitter<NzFormatEmitEvent>` | - |
 | `(nzDblClick)` | Callback function for when the user double clicks a treeNode | `EventEmitter<NzFormatEmitEvent>` | - |
 | `(nzContextMenu)` | Callback function for when the user right clicks a treeNode | `EventEmitter<NzFormatEmitEvent>` | - |

components/tree/doc/index.zh-CN.md

@@ -39,6 +39,10 @@ import { NzTreeModule } from 'ng-zorro-antd/tree';
 | `[nzSearchValue]` | 按需筛选树高亮节点(参考可搜索的树),双向绑定 | `string` | `null` |
 | `[nzSearchFunc]` | 自定义匹配方法，配合 nzSearchValue 使用 | `(node: NzTreeNodeOptions) => boolean` | `null` |
 | `[nzBeforeDrop]` | drop前二次校验,允许用户自行决定是否允许放置 | `(confirm: NzFormatBeforeDropEvent) => Observable<boolean>` | - |
+| `[nzVirtualHeight]` | 虚拟滚动的总高度 | `string` | `-` |
+| `[nzVirtualItemSize]` | 虚拟滚动时每一列的高度，与 [cdk itemSize](https://material.angular.io/cdk/scrolling/api) 相同 | `number` | `0` |
+| `[nzVirtualMaxBufferPx]` | 缓冲区最大像素高度，与 [cdk maxBufferPx](https://material.angular.io/cdk/scrolling/api) 相同 | `number` | `200` |
+| `[nzVirtualMinBufferPx]` | 缓冲区最小像素高度，低于该值时将加载新结构，与 [cdk minBufferPx](https://material.angular.io/cdk/scrolling/api) 相同 | `number` | `100` |
 | `(nzClick)` | 点击树节点触发 | `EventEmitter<NzFormatEmitEvent>` | - |
 | `(nzDblClick)` | 双击树节点触发 | `EventEmitter<NzFormatEmitEvent>` | - |
 | `(nzContextMenu)` | 右键树节点触发 | `EventEmitter<NzFormatEmitEvent>` | - |