feat(toastr): add toasts limit

src/app/playground-components.ts

@@ -1132,6 +1132,12 @@ export const PLAYGROUND_COMPONENTS: ComponentLink[] = [
         component: 'ToastrStatusesComponent',
         name: 'Toastr Statuses',
       },
+      {
+        path: 'toastr-limit.component',
+        link: '/toastr/toastr-limit.component',
+        component: 'ToastrLimitComponent',
+        name: 'Toastr Limit',
+      },
     ],
   },
   {

src/framework/theme/components/toastr/toastr-config.ts

@@ -47,6 +47,10 @@ export class NbToastrConfig {
    * Determines the how to threat duplicates.
    * */
   duplicatesBehaviour: NbDuplicateToastBehaviour = 'previous';
+  /*
+  * The number of visible toasts. If the limit exceeded the oldest toast will be removed.
+  * */
+  limit?: number = null;
   /**
    * Determines render icon or not.
    * */

src/framework/theme/components/toastr/toastr.service.spec.ts

@@ -256,7 +256,7 @@ describe('toastr-container', () => {
       config: { status: 'dander', preventDuplicates: true, duplicatesBehaviour: 'previous' },
     };
 
-    const toast2 = Object.assign({title: 'toast2'}, toast1);
+    const toast2 = Object.assign({}, toast1, {title: 'toast2'});
 
     toastrContainer.attach(<NbToast> toast1);
     toastrContainer.attach(<NbToast> toast2);
@@ -272,12 +272,54 @@ describe('toastr-container', () => {
       config: { status: 'dander', preventDuplicates: true, duplicatesBehaviour: 'all' },
     };
 
-    const toast2 = Object.assign({title: 'toast2'}, toast1);
+    const toast2 = Object.assign({}, toast1, {title: 'toast2'});
 
     toastrContainer.attach(<NbToast> toast1);
     toastrContainer.attach(<NbToast> toast2);
     const duplicateToast = toastrContainer.attach(<NbToast> toast1);
 
     expect(duplicateToast).toBeUndefined();
   });
+
+  describe('if limit set', () => {
+
+    const toast1 = {
+      title: 'toast1',
+      config: { limit: 3 },
+    };
+
+    const toast2 = Object.assign({}, toast1, {title: 'toast2'});
+    const toast3 = Object.assign({}, toast1, {title: 'toast3'});
+    const toast4 = Object.assign({}, toast1, {title: 'toast4'});
+
+    function attachToasts() {
+      toastrContainer.attach(<NbToast> toast1);
+      toastrContainer.attach(<NbToast> toast2);
+      toastrContainer.attach(<NbToast> toast3);
+      toastrContainer.attach(<NbToast> toast4);
+    }
+
+    it('should remove the first toast in container in top position', () => {
+      attachToasts();
+      expect(containerRefStub.instance.content.length).toEqual(3);
+      expect(containerRefStub.instance.content[0]).toEqual(toast4);
+      expect(containerRefStub.instance.content[1]).toEqual(toast3);
+      expect(containerRefStub.instance.content[2]).toEqual(toast2);
+    });
+    it('should remove the last toast in container in bottom position', () => {
+      positionHelperStub = {
+        isTopPosition() {
+          return false;
+        },
+      };
+
+      toastrContainer = new NbToastContainer(<any> {}, containerRefStub, positionHelperStub);
+
+      attachToasts();
+      expect(containerRefStub.instance.content.length).toEqual(3);
+      expect(containerRefStub.instance.content[0]).toEqual(toast2);
+      expect(containerRefStub.instance.content[1]).toEqual(toast3);
+      expect(containerRefStub.instance.content[2]).toEqual(toast4);
+    });
+  });
 });

src/framework/theme/components/toastr/toastr.service.ts

@@ -44,6 +44,7 @@ export class NbToastContainer {
       return;
     }
 
+    this.removeToastIfLimitReached(toast);
     const toastComponent: NbToastComponent = this.attachToast(toast);
 
     if (toast.config.destroyByClick) {
@@ -88,6 +89,17 @@ export class NbToastContainer {
       && t1.config.status === t2.config.status;
   };
 
+  protected removeToastIfLimitReached(toast: NbToast) {
+    if (!toast.config.limit || this.toasts.length < toast.config.limit) {
+      return;
+    }
+    if (this.positionHelper.isTopPosition(toast.config.position)) {
+      this.toasts.pop();
+    } else {
+      this.toasts.shift();
+    }
+  }
+
   protected attachToast(toast: NbToast): NbToastComponent {
     if (this.positionHelper.isTopPosition(toast.config.position)) {
       return this.attachToTop(toast);
@@ -220,11 +232,15 @@ export class NbToastrContainerRegistry {
  * @stacked-example(Prevent duplicates, toastr/toastr-prevent-duplicates.component)
  *
  * `duplicatesBehaviour` - determines how to threat the toasts duplication.
- * Compare with the previous message (`NbDuplicateToastBehaviour.PREVIOUS`)
- * or with all visible messages (`NbDuplicateToastBehaviour.ALL`).
+ * Compare with the previous message `previous`
+ * or with all visible messages `all`.
  *
  * @stacked-example(Prevent duplicates behaviour , toastr/toastr-prevent-duplicates-behaviour.component)
  *
+ * `limit` - the number of visible toasts in the toast container. The number of toasts is unlimited by default.
+ *
+ * @stacked-example(Prevent duplicates behaviour , toastr/toastr-limit.component)
+ *
  * `hasIcon` - if true then render toast icon.
  * `icon` - you can pass icon class that will be applied into the toast.
  *

src/playground/with-layout/toastr/toastr-limit.component.ts

@@ -0,0 +1,31 @@
+import { NbGlobalLogicalPosition, NbToastrService } from '@nebular/theme';
+import { Component } from '@angular/core';
+
+@Component({
+  selector: 'nb-toastr-limit',
+  template: `
+    <button nbButton (click)="showToast()">Show only 3 toasts</button>
+  `,
+  styles: [
+    `
+      ::ng-deep nb-layout-column {
+        height: 80vw;
+      }
+    `,
+  ],
+})
+export class ToastrLimitComponent {
+
+  constructor(private toastrService: NbToastrService) {
+  }
+
+  i: number = 1;
+
+  showToast() {
+    this.toastrService.show(
+      `Toast number ${this.i}`,
+      `Toast with the limit`,
+      { limit: 3, position: NbGlobalLogicalPosition.TOP_END });
+    this.i++;
+  }
+}

src/playground/with-layout/toastr/toastr-routing.module.ts

@@ -14,6 +14,7 @@ import { ToastrPreventDuplicatesComponent } from './toastr-prevent-duplicates.co
 import { ToastrShowcaseComponent } from './toastr-showcase.component';
 import { ToastrStatusesComponent } from './toastr-statuses.component';
 import { ToastrPreventDuplicatesBehaviourComponent } from './toastr-prevent-duplicates-behaviour.component';
+import { ToastrLimitComponent } from './toastr-limit.component';
 
 const routes: Route[] = [
   {
@@ -48,6 +49,10 @@ const routes: Route[] = [
     path: 'toastr-statuses.component',
     component: ToastrStatusesComponent,
   },
+  {
+    path: 'toastr-limit.component',
+    component: ToastrLimitComponent,
+  },
 ];
 
 @NgModule({

src/playground/with-layout/toastr/toastr.module.ts

@@ -14,6 +14,7 @@ import { ToastrPositionsComponent } from './toastr-positions.component';
 import { ToastrPreventDuplicatesComponent } from './toastr-prevent-duplicates.component';
 import { ToastrShowcaseComponent } from './toastr-showcase.component';
 import { ToastrStatusesComponent } from './toastr-statuses.component';
+import { ToastrLimitComponent } from './toastr-limit.component';
 import { ToastrPreventDuplicatesBehaviourComponent } from './toastr-prevent-duplicates-behaviour.component';
 import { CommonModule } from '@angular/common';
 import { FormsModule } from '@angular/forms';
@@ -28,6 +29,7 @@ import { FormsModule } from '@angular/forms';
     ToastrPreventDuplicatesBehaviourComponent,
     ToastrShowcaseComponent,
     ToastrStatusesComponent,
+    ToastrLimitComponent,
   ],
   imports: [
     CommonModule,