Adds expand/collapse button to menu

src/app/app.component.html

@@ -9,6 +9,10 @@
     fxLayoutAlign="center end"
     [ngClass]="{'scrolling': isScrolling}"
  >
+    <button mat-fab (click)="toggleMenu()" class="toggle-menu" color="primary">
+      <mat-icon *ngIf="!isScrolling">menu</mat-icon>
+      <mat-icon *ngIf="isScrolling">close</mat-icon>
+    </button>
     <a
       *ngFor="let link of menuLinks"
       mat-button

src/app/app.component.scss

@@ -15,6 +15,12 @@
     right: 0px;
   }
 
+  button.toggle-menu {
+    position: fixed;
+    top: 20px;
+    right: 20px;
+  }
+
   a {
     transition: all 1s ease-in-out 0.5s;
 

src/app/app.component.ts

@@ -79,4 +79,8 @@ export class AppComponent implements AfterViewInit {
     }, 2000);
   }
 
+  toggleMenu() {
+    this.isScrolling = !this.isScrolling;
+  }
+
 }