feat(module:select): select max tag count

components/select/demo/max-count.md

@@ -0,0 +1,14 @@
+---
+order: 26
+title:
+  zh-CN: 最大选中数量
+  en-US: Max Count
+---
+
+## zh-CN
+
+你可以通过设置 `nzMaxMultipleCount` 约束最多可选中的数量，当超出限制时会变成禁止选中状态。
+
+## en-US
+
+You can set the `nzMaxMultipleCount` prop to control the max number of items can be selected. When the limit is exceeded, the options will become disabled.

components/select/demo/max-count.ts

@@ -0,0 +1,36 @@
+import { Component, OnInit } from '@angular/core';
+
+@Component({
+  selector: 'nz-demo-select-max-count',
+  template: `
+    <nz-select
+      [nzMaxMultipleCount]="3"
+      nzMode="multiple"
+      nzPlaceHolder="Please select"
+      nzAllowClear
+      [nzShowArrow]="true"
+      [(ngModel)]="listOfSelectedValue"
+    >
+      <nz-option *ngFor="let item of listOfOption" [nzLabel]="item" [nzValue]="item"></nz-option>
+    </nz-select>
+  `,
+  styles: [
+    `
+      nz-select {
+        width: 100%;
+      }
+    `
+  ]
+})
+export class NzDemoSelectMaxCountComponent implements OnInit {
+  listOfOption: string[] = [];
+  listOfSelectedValue = ['a10', 'c12'];
+
+  ngOnInit(): void {
+    const children: string[] = [];
+    for (let i = 10; i < 36; i++) {
+      children.push(`${i.toString(36)}${i}`);
+    }
+    this.listOfOption = children;
+  }
+}

components/select/option-container.component.ts

@@ -66,7 +66,7 @@ import { NzSelectItemInterface, NzSelectModeType } from './select.types';
               [customContent]="item.nzCustomContent"
               [template]="item.template"
               [grouped]="!!item.groupLabel"
-              [disabled]="item.nzDisabled"
+              [disabled]="item.nzDisabled || (isMaxLimitReached && !listOfSelectedValue.includes(item['nzValue']))"
               [showState]="mode === 'tags' || mode === 'multiple'"
               [title]="item.nzTitle"
               [label]="item.nzLabel"
@@ -108,6 +108,7 @@ export class NzOptionContainerComponent implements OnChanges, AfterViewInit {
   @Input() matchWidth = true;
   @Input() itemSize = 32;
   @Input() maxItemLength = 8;
+  @Input() isMaxLimitReached = false;
   @Input() listOfContainerItem: NzSelectItemInterface[] = [];
   @Output() readonly itemClick = new EventEmitter<NzSafeAny>();
   @Output() readonly scrollToBottom = new EventEmitter<void>();

components/select/select-arrow.component.ts

@@ -15,6 +15,9 @@ import { NzIconModule } from 'ng-zorro-antd/icon';
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush,
   template: `
+    <ng-container *ngIf="isMaxTagCountSet">
+      <span>{{ listOfValue.length }} / {{ nzMaxMultipleCount }}</span>
+    </ng-container>
     <span nz-icon nzType="loading" *ngIf="loading; else defaultArrow"></span>
     <ng-template #defaultArrow>
       <ng-container *ngIf="showArrow && !suffixIcon; else suffixTemplate">
@@ -37,11 +40,14 @@ import { NzIconModule } from 'ng-zorro-antd/icon';
   standalone: true
 })
 export class NzSelectArrowComponent {
+  @Input() listOfValue: NzSafeAny[] = [];
   @Input() loading = false;
   @Input() search = false;
   @Input() showArrow = false;
+  @Input() isMaxTagCountSet = false;
   @Input() suffixIcon: TemplateRef<NzSafeAny> | string | null = null;
   @Input() feedbackIcon: TemplateRef<NzSafeAny> | string | null = null;
+  @Input() nzMaxMultipleCount: number = Infinity;
 
   constructor() {}
 }

components/select/select.component.ts

@@ -126,12 +126,15 @@ export type NzSelectSizeType = 'large' | 'default' | 'small';
       (keydown)="onKeyDown($event)"
     ></nz-select-top-control>
     <nz-select-arrow
-      *ngIf="nzShowArrow || (hasFeedback && !!status)"
+      *ngIf="nzShowArrow || (hasFeedback && !!status) || isMaxTagCountSet"
       [showArrow]="nzShowArrow"
       [loading]="nzLoading"
       [search]="nzOpen && nzShowSearch"
       [suffixIcon]="nzSuffixIcon"
       [feedbackIcon]="feedbackIconTpl"
+      [nzMaxMultipleCount]="nzMaxMultipleCount"
+      [listOfValue]="listOfValue"
+      [isMaxTagCountSet]="isMaxTagCountSet"
     >
       <ng-template #feedbackIconTpl>
         <nz-form-item-feedback-icon *ngIf="hasFeedback && !!status" [status]="status"></nz-form-item-feedback-icon>
@@ -178,6 +181,7 @@ export type NzSelectSizeType = 'large' | 'default' | 'small';
         [dropdownRender]="nzDropdownRender"
         [compareWith]="compareWith"
         [mode]="nzMode"
+        [isMaxLimitReached]="isMaxLimitReached"
         (keydown)="onKeyDown($event)"
         (itemClick)="onItemClick($event)"
         (scrollToBottom)="nzScrollToBottom.emit()"
@@ -275,6 +279,10 @@ export class NzSelectComponent implements ControlValueAccessor, OnInit, AfterCon
     return this._nzShowArrow === undefined ? this.nzMode === 'default' : this._nzShowArrow;
   }
 
+  get isMaxTagCountSet(): boolean {
+    return this.nzMaxMultipleCount !== Infinity;
+  }
+
   @Output() readonly nzOnSearch = new EventEmitter<string>();
   @Output() readonly nzScrollToBottom = new EventEmitter<void>();
   @Output() readonly nzOpenChange = new EventEmitter<boolean>();
@@ -309,6 +317,7 @@ export class NzSelectComponent implements ControlValueAccessor, OnInit, AfterCon
   focused = false;
   dir: Direction = 'ltr';
   positions: ConnectionPositionPair[] = [];
+  isMaxLimitReached = false;
 
   // status
   prefixCls: string = 'ant-select';
@@ -422,6 +431,9 @@ export class NzSelectComponent implements ControlValueAccessor, OnInit, AfterCon
       this.value = model;
       this.onChange(this.value);
     }
+
+    this.isMaxLimitReached =
+      this.nzMaxMultipleCount !== Infinity && this.listOfValue.length === this.nzMaxMultipleCount;
   }
 
   onTokenSeparate(listOfLabel: string[]): void {

components/select/select.spec.ts

@@ -1270,7 +1270,15 @@ describe('select', () => {
       flushRefresh();
       expect(component.value.length).toBe(1);
       expect(component.value[0]).toBe('test_01');
+      expect(listOfContainerItem[1]).toHaveClass('ant-select-item-option-disabled');
     }));
+    it('should show nzShowArrow component when having nzMaxMultipleCount', () => {
+      component.nzMaxMultipleCount = 0;
+      expect(selectElement.querySelector('nz-select-arrow')).toBeFalsy();
+      component.nzMaxMultipleCount = 1;
+      fixture.detectChanges();
+      expect(selectElement.querySelector('nz-select-arrow')).toBeTruthy();
+    });
     it('should nzAutoClearSearchValue work', fakeAsync(() => {
       const flushRefresh = (): void => {
         fixture.detectChanges();
@@ -1425,6 +1433,33 @@ describe('select', () => {
       // expect(requestAnimationFrameSpy).toHaveBeenCalledTimes(2);
     }));
 
+    it('should isMaxTagCountSet work correct', () => {
+      component.nzMaxMultipleCount = Infinity;
+      fixture.detectChanges();
+      let isMaxTagCountSet;
+      isMaxTagCountSet = selectComponent['isMaxTagCountSet'];
+      expect(isMaxTagCountSet).toBeFalsy();
+
+      component.nzMaxMultipleCount = 1;
+      fixture.detectChanges();
+      isMaxTagCountSet = selectComponent['isMaxTagCountSet'];
+      expect(isMaxTagCountSet).toBeTruthy();
+    });
+
+    it('should isMaxLimitReached be set correctly', () => {
+      selectComponent.nzMaxMultipleCount = 2;
+      selectComponent.listOfValue = ['a', 'b'];
+      fixture.detectChanges();
+      selectComponent.updateListOfValue(['a', 'b']);
+      expect(selectComponent.isMaxLimitReached).toBeTruthy();
+
+      selectComponent.nzMaxMultipleCount = 20;
+      selectComponent.listOfValue = ['a', 'b'];
+      fixture.detectChanges();
+      selectComponent.updateListOfValue(['a', 'b']);
+      expect(selectComponent.isMaxLimitReached).toBeFalsy();
+    });
+
     it('should not run change detection when `nz-select-top-control` is clicked and should focus the `nz-select-search`', () => {
       const appRef = TestBed.inject(ApplicationRef);
       spyOn(appRef, 'tick');
@@ -1625,6 +1660,7 @@ describe('select', () => {
       [(nzOpen)]="nzOpen"
       [nzPlacement]="nzPlacement"
       [nzSelectOnTab]="nzSelectOnTab"
+      [nzMaxMultipleCount]="nzMaxMultipleCount"
       (ngModelChange)="valueChange($event)"
       (nzOnSearch)="searchValueChange($event)"
       (nzOpenChange)="openChange($event)"
@@ -1671,6 +1707,7 @@ export class TestSelectTemplateDefaultComponent {
   nzSuffixIcon: TemplateRef<NzSafeAny> | null = null;
   nzClearIcon: TemplateRef<NzSafeAny> | null = null;
   nzShowArrow = true;
+  nzMaxMultipleCount: number = Infinity;
   nzFilterOption: NzFilterOptionType = (searchValue: string, item: NzSelectItemInterface): boolean => {
     if (item && item.nzLabel) {
       return item.nzLabel.toString().toLowerCase().indexOf(searchValue.toLowerCase()) > -1;