create chart item state to toggle filter selection

src/app/charts/chart-item/chart-item.component.html

@@ -1,4 +1,4 @@
-<div fxLayout="row" fxLayoutAlign="space-between start" class="item">
+<div fxLayout="row" fxLayoutAlign="space-between start" [ngClass]="(_selected)?'item selected':'item'">
     <div><a href="#">{{state}}</a>: &nbsp;</div>
     <div>{{count}}</div>
 </div>

src/app/charts/chart-item/chart-item.component.scss

@@ -1,3 +1,13 @@
 .item {
     cursor: pointer;
+    padding: 3px;
+    border-radius: 4px;
+}
+
+.selected {
+    background-color: #DDDDDD;
+}
+.selected a {
+    color: #000000;
+    text-decoration: none;
 }

src/app/charts/chart-item/chart-item.component.ts

@@ -8,6 +8,12 @@ import { Component, Input } from '@angular/core';
 export class ChartItemComponent {
   @Input() state: string;
   @Input() count: number;
+  @Input('selected')
+  set selected(s: boolean) {
+    this._selected = s;
+  }
+
+  _selected: boolean = true;
 
   constructor() { }
 }