date diff pipe

src/app/app.module.ts

@@ -56,6 +56,7 @@ import { CreateProjectTypeComponent } from './modules/customer-management/compon
 import { CustomerEffects } from './modules/customer-management/store/customer-management.effects';
 import { EntryEffects } from './modules/time-clock/store/entry.effects';
 import { InjectTokenInterceptor } from './modules/shared/interceptors/inject.token.interceptor';
+import { SubstractDatePipe } from './modules/shared/pipes/substract-date/substract-date.pipe';
 
 @NgModule({
   declarations: [
@@ -90,6 +91,7 @@ import { InjectTokenInterceptor } from './modules/shared/interceptors/inject.tok
     ProjectTypeListComponent,
     CreateProjectTypeComponent,
     EntryFieldsComponent,
+    SubstractDatePipe,
   ],
   imports: [
     CommonModule,

src/app/modules/shared/pipes/substract-date/substract-date.pipe.spec.ts

@@ -0,0 +1,17 @@
+import { SubstractDatePipe } from './substract-date.pipe';
+
+describe('SubstractDatePipe', () => {
+  it('create an instance', () => {
+    const pipe = new SubstractDatePipe();
+    expect(pipe).toBeTruthy();
+  });
+
+  it('returns the date diff', () => {
+    const fromDate = new Date('2011-04-11T10:20:30Z');
+    const substractDate = new Date('2011-04-11T08:00:30Z');
+
+    const diff = new SubstractDatePipe().transform(fromDate, substractDate);
+
+    expect(diff).toBe('02:20');
+  });
+});

src/app/modules/shared/pipes/substract-date/substract-date.pipe.ts

@@ -0,0 +1,22 @@
+import { Pipe, PipeTransform } from '@angular/core';
+
+@Pipe({
+  name: 'substractDate'
+})
+export class SubstractDatePipe implements PipeTransform {
+
+  transform(fromDate: Date, substractDate: Date): string {
+    const difference = fromDate.valueOf() - substractDate.valueOf();
+
+    const minutes = Math.floor((difference / (1000 * 60)) % 60);
+    const hours = Math.floor(difference / (1000 * 60 * 60) % 24);
+
+    return `${this.formatTime(hours)}:${this.formatTime(minutes)}`;
+  }
+
+  formatTime(time: number): string {
+    const formattedTime = (time < 10) ? '0' + time : time.toString();
+    return formattedTime;
+  }
+
+}