test.component.html

  <span i18n>This is testfile</span>
  <br />
  <br />
  <br />

  <h1 i18n>Counter value</h1>
  {{counter}}

<p i18n>{counter, plural, =0 {not pressed} =1 {pressed once} other {pressed many times}} </p>

  <button (click)="addOne()" i18n>ADD ONE</button>

  <span i18n>This is testfile</span>