Observables and Promises

• Promises and functions that return promises
• Create an observable manually
• Observable operators such as:
  • Retry
  • Map
  • Filter
  • Next
• Functions that return observables
• Current page tracking component
• Observables to read route configuration parameters that are different from route parameters by url
• Change the metatags depending on the page where we are
• Change the title of the current page