title: How to trigger an action based on the user's view on the page in Angular?
body: <p>I want to have a single page in Angular with multiple subsections which can be either reached by seemless scrolling down or by clicking on the list of sections.
  If the user clicks on the section, an action to scroll into the section is triggered and the particular section is highlighted in which the user is currently located in the page.</p>
  <p>How is it possible to track when the user reaches a specific section by scrolling to trigger the colour highlighting correctly?</p>