install heatmapjs npm i heatmapjs --save app.module

import { AngularHeatmapModule } from 'ng-heatmap';
imports: [
    ...
    AngularHeatmapModule,
    ...
  ],

in project <ng-heatmap [active]="true" [hidden]="false" [(heatmapData)]="twoWayBind"></ng-heatmap>

Default class .heatmap can be overwritten by passing class property to <ng-heatmap> component.

.heatmap {
  position: absolute;
  top: 0;
  left: 0;
  height: 100vh;
  width: 100vw;
  opacity: .5;
  z-index: 9;
}