[Feature] Custom no entries found element (#382)

* add ngxMatSelectNoEntriesFound directive

* change ngx-mat-select-search to use ngxMatSelectNoEntriesFound directive

* add custom no entries found element example

* rename no entries found example component

* export MatSelectNoEntriesFoundDirective in NgxMatSelectSearchModule

* fix typo

* format mat-select-search.component.html

* move custom-no-entries-found-example.component

* add README.md entry for customize no entries found element

* adjust custom no entries found example

Co-authored-by: Esteban Gehring <esteban.gehring@bithost.ch>

README.md

@@ -191,6 +191,19 @@ In order to customize the search icon, add the `ngxMatSelectSearchClear` to your
 ```
 If just the icon should be changed the inputs `closeIcon` and `closeSvgIcon` can be used.
 
+#### Customize no entries found element
+In order to customize the no entries found element, add the `ngxMatSelectNoEntriesFound` to your custom item (a `mat-icon, span, button` or any other element) and place it inside the `ngx-mat-select-search` component:
+```html
+<ngx-mat-select-search>
+  <span ngxMatSelectNoEntriesFound>
+    No entries found
+    <button mat-button color="primary">
+      Add <mat-icon>add</mat-icon>
+    </button>
+</span>
+</ngx-mat-select-search>
+```
+
 #### Custom content
 Custom content with the CSS class `mat-select-search-custom-header-content` can be transcluded as follows:
 ```html

src/app/app.component.html

@@ -17,6 +17,8 @@ <h2>Examples</h2>
 
   <app-custom-clear-icon-example></app-custom-clear-icon-example>
 
+  <app-custom-no-entries-found-example></app-custom-no-entries-found-example>
+
   <app-option-groups-example></app-option-groups-example>
 
   <app-server-side-search-example></app-server-side-search-example>

src/app/app.module.ts

@@ -23,6 +23,7 @@ import {
 } from './examples/06-multiple-selection-select-all-example/multiple-selection-select-all-example.component';
 import { TooltipSelectAllExampleComponent } from './examples/07-tooltip-select-all-example/tooltip-select-all-example.component';
 import { InfiniteScrollExampleComponent } from './examples/08-infinite-scroll-example/infinite-scroll-example.component';
+import { CustomNoEntriesFoundExampleComponent } from './examples/09-custom-no-entries-found-example/custom-no-entries-found-example.component';
 import { MatSlideToggleModule } from '@angular/material/slide-toggle';
 
 
@@ -56,6 +57,7 @@ export class MaterialModule {}
     SingleSelectionExampleComponent,
     MultipleSelectionExampleComponent,
     CustomClearIconExampleComponent,
+    CustomNoEntriesFoundExampleComponent,
     OptionGroupsExampleComponent,
     ServerSideSearchExampleComponent,
     MultipleSelectionSelectAllExampleComponent,

src/app/examples/09-custom-no-entries-found-example/custom-no-entries-found-example.component.html

@@ -0,0 +1,23 @@
+<h3>Single selection with custom no entries found element</h3>
+<p>
+  <mat-form-field>
+    <mat-select [formControl]="bankCtrl" placeholder="Bank" #singleSelect>
+      <mat-option>
+        <ngx-mat-select-search *ngIf="true" [formControl]="bankFilterCtrl" [preventHomeEndKeyPropagation]="true">
+          <span ngxMatSelectNoEntriesFound>
+            No entries found
+            <button mat-button color="primary">
+              Add <mat-icon>add</mat-icon>
+            </button>
+          </span>
+        </ngx-mat-select-search>
+      </mat-option>
+      <mat-option *ngFor="let bank of filteredBanks | async" [value]="bank">
+        {{bank.name}}
+      </mat-option>
+    </mat-select>
+  </mat-form-field>
+</p>
+<p>
+  Selected Bank: {{bankCtrl.value?.name}}
+</p>

src/app/examples/09-custom-no-entries-found-example/custom-no-entries-found-example.component.ts

@@ -0,0 +1,92 @@
+import { AfterViewInit, Component, OnDestroy, OnInit, ViewChild } from '@angular/core';
+import { Bank, BANKS } from '../demo-data';
+import { FormControl } from '@angular/forms';
+import { ReplaySubject, Subject } from 'rxjs';
+import { MatSelect } from '@angular/material/select';
+import { take, takeUntil } from 'rxjs/operators';
+
+@Component({
+  selector: 'app-custom-no-entries-found-example',
+  templateUrl: './custom-no-entries-found-example.component.html',
+  styleUrls: ['./custom-no-entries-found-example.component.scss']
+})
+export class CustomNoEntriesFoundExampleComponent implements OnInit, AfterViewInit, OnDestroy {
+
+  /** list of banks */
+  protected banks: Bank[] = BANKS;
+
+  /** control for the selected bank */
+  public bankCtrl: FormControl = new FormControl();
+
+  /** control for the MatSelect filter keyword */
+  public bankFilterCtrl: FormControl = new FormControl();
+
+  /** list of banks filtered by search keyword */
+  public filteredBanks: ReplaySubject<Bank[]> = new ReplaySubject<Bank[]>(1);
+
+  @ViewChild('singleSelect', { static: true }) singleSelect: MatSelect;
+
+  /** Subject that emits when the component has been destroyed. */
+  protected _onDestroy = new Subject<void>();
+
+
+  constructor() { }
+
+  ngOnInit() {
+    // set initial selection
+    this.bankCtrl.setValue(this.banks[10]);
+
+    // load the initial bank list
+    this.filteredBanks.next(this.banks.slice());
+
+    // listen for search field value changes
+    this.bankFilterCtrl.valueChanges
+      .pipe(takeUntil(this._onDestroy))
+      .subscribe(() => {
+        this.filterBanks();
+      });
+  }
+
+  ngAfterViewInit() {
+    this.setInitialValue();
+  }
+
+  ngOnDestroy() {
+    this._onDestroy.next();
+    this._onDestroy.complete();
+  }
+
+  /**
+   * Sets the initial value after the filteredBanks are loaded initially
+   */
+  protected setInitialValue() {
+    this.filteredBanks
+      .pipe(take(1), takeUntil(this._onDestroy))
+      .subscribe(() => {
+        // setting the compareWith property to a comparison function
+        // triggers initializing the selection according to the initial value of
+        // the form control (i.e. _initializeSelection())
+        // this needs to be done after the filteredBanks are loaded initially
+        // and after the mat-option elements are available
+        this.singleSelect.compareWith = (a: Bank, b: Bank) => a && b && a.id === b.id;
+      });
+  }
+
+  protected filterBanks() {
+    if (!this.banks) {
+      return;
+    }
+    // get the search keyword
+    let search = this.bankFilterCtrl.value;
+    if (!search) {
+      this.filteredBanks.next(this.banks.slice());
+      return;
+    } else {
+      search = search.toLowerCase();
+    }
+    // filter the banks
+    this.filteredBanks.next(
+      this.banks.filter(bank => bank.name.toLowerCase().indexOf(search) > -1)
+    );
+  }
+}

src/app/mat-select-search/mat-select-no-entries-found.directive.ts

@@ -0,0 +1,15 @@
+import { Directive } from '@angular/core';
+
+/**
+ * Directive for providing a custom no entries found element.
+ * e.g.
+ * <ngx-mat-select-search [formControl]="bankFilterCtrl">
+ *   <span ngxMatSelectNoEntriesFound>
+ *     No entries found <button>Add</button>
+ *   </span>
+ * </ngx-mat-select-search>
+ */
+@Directive({
+  selector: '[ngxMatSelectNoEntriesFound]'
+})
+export class MatSelectNoEntriesFoundDirective {}

src/app/mat-select-search/mat-select-search.component.html

@@ -53,7 +53,9 @@
 
 <div *ngIf="_showNoEntriesFound$ | async"
      class="mat-select-search-no-entries-found">
-  {{noEntriesFoundLabel}}
+  <ng-content *ngIf="noEntriesFound; else defaultNoEntriesFound"
+              select="[ngxMatSelectNoEntriesFound]"></ng-content>
+  <ng-template #defaultNoEntriesFound>{{noEntriesFoundLabel}}</ng-template>
 </div>
 <!--
 Copyright (c) 2018 Bithost GmbH All Rights Reserved.

src/app/mat-select-search/mat-select-search.component.ts

@@ -35,6 +35,7 @@ import { BehaviorSubject, combineLatest, Observable, of, Subject } from 'rxjs';
 import { delay, filter, map, startWith, switchMap, take, takeUntil, tap } from 'rxjs/operators';
 import { MatSelectSearchClearDirective } from './mat-select-search-clear.directive';
 import { configurableDefaultOptions, MAT_SELECTSEARCH_DEFAULT_OPTIONS, MatSelectSearchOptions } from './default-options';
+import { MatSelectNoEntriesFoundDirective } from './mat-select-no-entries-found.directive';
 
 
 /** The max height of the select's overlay panel. */
@@ -219,6 +220,9 @@ export class MatSelectSearchComponent implements OnInit, OnDestroy, ControlValue
   /** Reference to custom search input clear icon */
   @ContentChild(MatSelectSearchClearDirective) clearIcon: MatSelectSearchClearDirective;
 
+  /** Reference to custom no entries found element */
+  @ContentChild(MatSelectNoEntriesFoundDirective) noEntriesFound: MatSelectNoEntriesFoundDirective;
+
   @HostBinding('class.mat-select-search-inside-mat-option')
   get isInsideMatOption(): boolean {
     return !!this.matOption;

src/app/mat-select-search/ngx-mat-select-search.module.ts

@@ -16,9 +16,11 @@ import { CommonModule } from '@angular/common';
 
 import { MatSelectSearchClearDirective } from './mat-select-search-clear.directive';
 import { ReactiveFormsModule } from '@angular/forms';
+import { MatSelectNoEntriesFoundDirective } from './mat-select-no-entries-found.directive';
 
 export const MatSelectSearchVersion = '4.1.2';
 export { MatSelectSearchClearDirective };
+export { MatSelectNoEntriesFoundDirective };
 
 @NgModule({
   imports: [
@@ -32,11 +34,13 @@ export { MatSelectSearchClearDirective };
   ],
   declarations: [
     MatSelectSearchComponent,
-    MatSelectSearchClearDirective
+    MatSelectSearchClearDirective,
+    MatSelectNoEntriesFoundDirective
   ],
   exports: [
     MatSelectSearchComponent,
-    MatSelectSearchClearDirective
+    MatSelectSearchClearDirective,
+    MatSelectNoEntriesFoundDirective
   ]
 })
 export class NgxMatSelectSearchModule {