In case your an absolute beginner with Angular, I will quickly explain that What Angular is and Why we should learn Angular.
What is Angular?
Typescript is more common in the Angular community because Angular itself built using TypeScript
Get started learning Angular by doing Development Setup here – Setting up Angular Development Environment
Why do we need Angular?
Benefits of Using Angular
Clean Structure – Angular gives our applications a Clean and Loosely coupled structure that is easy to understand and easy to maintain.
Code Reusability – Angular also brings in lot of utility code that we can reuse in various applications specially when dealing with users navigations and the browser history
Easy to Test – Applications built with Angular are more testable so we can easily write automated tests to test various parts of our application
So to conclude and answer the question Do we need Angular? – No it is not a compulsory to use Angular to built web applications but using Angular will make your life a lot easier as a developer so it is great advantage of using Angular.
I think next if you are absolute beginner on Angular then I would recommenced you read and understand Architecture of Angular Applications