feat(module:tree-view): add tree-view component

close NG-ZORRO#5976, close NG-ZORRO#5809, close NG-ZORRO#5739, close NG-ZORRO#5736, close NG-ZORRO#5519, close NG-ZORRO#5446, close NG-ZORRO#5152, close NG-ZORRO#4694, close NG-ZORRO#4472, close NG-ZORRO#3832, close NG-ZORRO#2785, close NG-ZORRO#2744

components/components.less

@@ -55,6 +55,7 @@
 @import "./auto-complete/style/entry.less";
 @import "./cascader/style/entry.less";
 @import "./tree/style/entry.less";
+@import "./tree-view/style/entry.less";
 @import "./tree-select/style/entry.less";
 @import "./calendar/style/entry.less";
 @import "./result/style/entry.less";

components/core/animation/collapse.ts

@@ -19,17 +19,22 @@ export const collapseMotion: AnimationTriggerMetadata = trigger('collapseMotion'
 export const treeCollapseMotion: AnimationTriggerMetadata = trigger('treeCollapseMotion', [
   transition('* => *', [
     query(
-      'nz-tree-node:leave',
-      [style({ overflow: 'hidden' }), stagger(0, [animate(`150ms ${AnimationCurves.EASE_IN_OUT}`, style({ height: 0 }))])],
+      'nz-tree-node:leave,nz-tree-builtin-node:leave',
+      [
+        style({ overflow: 'hidden' }),
+        stagger(0, [animate(`150ms ${AnimationCurves.EASE_IN_OUT}`, style({ height: 0, opacity: 0, 'padding-bottom': 0 }))])
+      ],
       {
         optional: true
       }
     ),
     query(
-      'nz-tree-node:enter',
+      'nz-tree-node:enter,nz-tree-builtin-node:enter',
       [
-        style({ overflow: 'hidden', height: 0 }),
-        stagger(0, [animate(`150ms ${AnimationCurves.EASE_IN_OUT}`, style({ overflow: 'hidden', height: '*' }))])
+        style({ overflow: 'hidden', height: 0, opacity: 0, 'padding-bottom': 0 }),
+        stagger(0, [
+          animate(`150ms ${AnimationCurves.EASE_IN_OUT}`, style({ overflow: 'hidden', height: '*', opacity: '*', 'padding-bottom': '*' }))
+        ])
       ],
       {
         optional: true

components/style/patch.less

@@ -11,6 +11,20 @@
   z-index: 1000;
 }
 
+.cdk-visually-hidden {
+  border: 0;
+  clip: rect(0 0 0 0);
+  height: 1px;
+  margin: -1px;
+  overflow: hidden;
+  padding: 0;
+  position: absolute;
+  width: 1px;
+  outline: 0;
+  -webkit-appearance: none;
+  -moz-appearance: none;
+}
+
 .cdk-overlay-backdrop {
   top: 0;
   bottom: 0;

components/tree-select/style/patch.less

@@ -1,4 +1,4 @@
-.ant-tree.ant-select-tree.ant-tree-show-line nz-tree-node:not(:last-child) > li::before {
+.ant-tree.ant-select-tree.ant-tree-show-line nz-tree-builtin-node:not(:last-child) > li::before {
   content: ' ';
   width: 1px;
   border-left: 1px solid #d9d9d9;

components/tree-select/tree-select.spec.ts

@@ -325,7 +325,7 @@ describe('tree-select component', () => {
       treeSelect.nativeElement.click();
       fixture.detectChanges();
       expect(treeSelectComponent.nzOpen).toBe(true);
-      node = overlayContainerElement.querySelector('nz-tree-node')!;
+      node = overlayContainerElement.querySelector('nz-tree-builtin-node')!;
       dispatchMouseEvent(node, 'click');
       fixture.detectChanges();
       flush();
@@ -447,7 +447,7 @@ describe('tree-select component', () => {
       fixture.detectChanges();
       expect(treeSelectComponent.nzOpen).toBe(true);
       fixture.detectChanges();
-      const targetNode = overlayContainerElement.querySelectorAll('nz-tree-node')[2];
+      const targetNode = overlayContainerElement.querySelectorAll('nz-tree-builtin-node')[2];
       dispatchMouseEvent(targetNode, 'click');
       fixture.detectChanges();
       flush();

components/tree-view/checkbox.ts

@@ -0,0 +1,39 @@
+/**
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/LICENSE
+ */
+
+import { ChangeDetectionStrategy, Component, EventEmitter, Input, Output } from '@angular/core';
+
+import { BooleanInput } from 'ng-zorro-antd/core/types';
+import { InputBoolean } from 'ng-zorro-antd/core/util';
+
+@Component({
+  selector: 'nz-tree-node-checkbox',
+  template: `
+    <span class="ant-tree-checkbox-inner"></span>
+  `,
+  changeDetection: ChangeDetectionStrategy.OnPush,
+  preserveWhitespaces: false,
+  host: {
+    class: 'ant-tree-checkbox',
+    '[class.ant-tree-checkbox-checked]': `nzChecked`,
+    '[class.ant-tree-checkbox-indeterminate]': `nzIndeterminate`,
+    '[class.ant-tree-checkbox-disabled]': `nzDisabled`,
+    '(click)': 'onClick($event)'
+  }
+})
+export class NzTreeNodeCheckboxComponent {
+  static ngAcceptInputType_nzDisabled: BooleanInput;
+
+  @Input() nzChecked?: boolean;
+  @Input() nzIndeterminate?: boolean;
+  @Input() @InputBoolean() nzDisabled?: boolean;
+  @Output() readonly nzClick = new EventEmitter<MouseEvent>();
+
+  onClick(e: MouseEvent): void {
+    if (!this.nzDisabled) {
+      this.nzClick.emit(e);
+    }
+  }
+}

components/tree-view/data-source.ts

@@ -0,0 +1,117 @@
+/**
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/LICENSE
+ */
+
+import { CollectionViewer, DataSource } from '@angular/cdk/collections';
+import { FlatTreeControl, TreeControl } from '@angular/cdk/tree';
+import { BehaviorSubject, merge, Observable } from 'rxjs';
+import { map, take } from 'rxjs/operators';
+
+export class NzTreeFlattener<T, F, K = F> {
+  constructor(
+    public transformFunction: (node: T, level: number) => F,
+    public getLevel: (node: F) => number,
+    public isExpandable: (node: F) => boolean,
+    public getChildren: (node: T) => Observable<T[]> | T[] | undefined | null
+  ) {}
+
+  private flattenNode(node: T, level: number, resultNodes: F[], parentMap: boolean[]): F[] {
+    const flatNode = this.transformFunction(node, level);
+    resultNodes.push(flatNode);
+
+    if (this.isExpandable(flatNode)) {
+      const childrenNodes = this.getChildren(node);
+      if (childrenNodes) {
+        if (Array.isArray(childrenNodes)) {
+          this.flattenChildren(childrenNodes, level, resultNodes, parentMap);
+        } else {
+          childrenNodes.pipe(take(1)).subscribe(children => {
+            this.flattenChildren(children, level, resultNodes, parentMap);
+          });
+        }
+      }
+    }
+    return resultNodes;
+  }
+
+  private flattenChildren(children: T[], level: number, resultNodes: F[], parentMap: boolean[]): void {
+    children.forEach((child, index) => {
+      const childParentMap: boolean[] = parentMap.slice();
+      childParentMap.push(index !== children.length - 1);
+      this.flattenNode(child, level + 1, resultNodes, childParentMap);
+    });
+  }
+
+  /**
+   * Flatten a list of node type T to flattened version of node F.
+   * Please note that type T may be nested, and the length of `structuredData` may be different
+   * from that of returned list `F[]`.
+   */
+  flattenNodes(structuredData: T[]): F[] {
+    const resultNodes: F[] = [];
+    structuredData.forEach(node => this.flattenNode(node, 0, resultNodes, []));
+    return resultNodes;
+  }
+
+  /**
+   * Expand flattened node with current expansion status.
+   * The returned list may have different length.
+   */
+  expandFlattenedNodes(nodes: F[], treeControl: TreeControl<F, K>): F[] {
+    const results: F[] = [];
+    const currentExpand: boolean[] = [];
+    currentExpand[0] = true;
+
+    nodes.forEach(node => {
+      let expand = true;
+      for (let i = 0; i <= this.getLevel(node); i++) {
+        expand = expand && currentExpand[i];
+      }
+      if (expand) {
+        results.push(node);
+      }
+      if (this.isExpandable(node)) {
+        currentExpand[this.getLevel(node) + 1] = treeControl.isExpanded(node);
+      }
+    });
+    return results;
+  }
+}
+
+export class NzTreeFlatDataSource<T, F, K = F> extends DataSource<F> {
+  _flattenedData = new BehaviorSubject<F[]>([]);
+
+  _expandedData = new BehaviorSubject<F[]>([]);
+
+  _data: BehaviorSubject<T[]>;
+
+  constructor(private _treeControl: FlatTreeControl<F, K>, private _treeFlattener: NzTreeFlattener<T, F, K>, initialData: T[] = []) {
+    super();
+    this._data = new BehaviorSubject<T[]>(initialData);
+  }
+
+  setData(value: T[]): void {
+    this._data.next(value);
+    this._flattenedData.next(this._treeFlattener.flattenNodes(this.getData()));
+    this._treeControl.dataNodes = this._flattenedData.value;
+  }
+
+  getData(): T[] {
+    return this._data.getValue();
+  }
+
+  connect(collectionViewer: CollectionViewer): Observable<F[]> {
+    const changes = [collectionViewer.viewChange, this._treeControl.expansionModel.changed, this._flattenedData];
+    return merge(...changes).pipe(
+      map(() => {
+        this._expandedData.next(this._treeFlattener.expandFlattenedNodes(this._flattenedData.value, this._treeControl));
+        return this._expandedData.value;
+      })
+    );
+  }
+
+  disconnect(): void {
+    // no op
+  }
+}

components/tree-view/demo/basic.md

@@ -0,0 +1,14 @@
+---
+order: 0
+title:
+  zh-CN: 基本
+  en-US: basic
+---
+
+## zh-CN
+
+最简单的用法，选中，禁用，展开等功能。
+
+## en-US
+
+The most basic usage including select, disable and expand features.

components/tree-view/demo/basic.ts

@@ -0,0 +1,98 @@
+import { SelectionModel } from '@angular/cdk/collections';
+import { FlatTreeControl } from '@angular/cdk/tree';
+import { Component } from '@angular/core';
+
+import { NzTreeFlatDataSource, NzTreeFlattener } from 'ng-zorro-antd/tree-view';
+
+interface TreeNode {
+  name: string;
+  disabled?: boolean;
+  children?: TreeNode[];
+}
+
+const TREE_DATA: TreeNode[] = [
+  {
+    name: 'parent 1',
+    children: [
+      {
+        name: 'parent 1-0',
+        disabled: true,
+        children: [{ name: 'leaf' }, { name: 'leaf' }]
+      },
+      {
+        name: 'parent 1-1',
+        children: [{ name: 'leaf' }]
+      }
+    ]
+  }
+];
+
+interface FlatNode {
+  expandable: boolean;
+  name: string;
+  level: number;
+  disabled: boolean;
+}
+
+@Component({
+  selector: 'nz-demo-tree-view-basic',
+  template: `
+    <nz-tree-view [nzTreeControl]="treeControl" [nzDataSource]="dataSource">
+      <nz-tree-node *nzTreeNodeDef="let node" nzTreeNodePadding>
+        <nz-tree-node-toggle nzTreeNodeNoopToggle></nz-tree-node-toggle>
+        <nz-tree-node-option
+          [nzDisabled]="node.disabled"
+          [nzSelected]="selectListSelection.isSelected(node)"
+          (nzClick)="selectListSelection.toggle(node)"
+        >
+          {{ node.name }}
+        </nz-tree-node-option>
+      </nz-tree-node>
+
+      <nz-tree-node *nzTreeNodeDef="let node; when: hasChild" nzTreeNodePadding>
+        <nz-tree-node-toggle>
+          <i nz-icon nzType="caret-down" nzTreeNodeToggleRotateIcon></i>
+        </nz-tree-node-toggle>
+        <nz-tree-node-option
+          [nzDisabled]="node.disabled"
+          [nzSelected]="selectListSelection.isSelected(node)"
+          (nzClick)="selectListSelection.toggle(node)"
+        >
+          {{ node.name }}
+        </nz-tree-node-option>
+      </nz-tree-node>
+    </nz-tree-view>
+  `
+})
+export class NzDemoTreeViewBasicComponent {
+  private transformer = (node: TreeNode, level: number) => {
+    return {
+      expandable: !!node.children && node.children.length > 0,
+      name: node.name,
+      level: level,
+      disabled: !!node.disabled
+    };
+  };
+  selectListSelection = new SelectionModel<FlatNode>(true);
+
+  treeControl = new FlatTreeControl<FlatNode>(
+    node => node.level,
+    node => node.expandable
+  );
+
+  treeFlattener = new NzTreeFlattener(
+    this.transformer,
+    node => node.level,
+    node => node.expandable,
+    node => node.children
+  );
+
+  dataSource = new NzTreeFlatDataSource(this.treeControl, this.treeFlattener);
+
+  constructor() {
+    this.dataSource.setData(TREE_DATA);
+    this.treeControl.expandAll();
+  }
+
+  hasChild = (_: number, node: FlatNode) => node.expandable;
+}

components/tree-view/demo/checkbox.md

@@ -0,0 +1,14 @@
+---
+order: 1
+title:
+  zh-CN: 选择框
+  en-US: checkbox
+---
+
+## zh-CN
+
+带选择框的树。
+
+## en-US
+
+Tree with checkboxes.