Is WebStorm needed if you have a Rider license?

Background/Situation [Optional]

On the Rider website it is written that Angular is also supported.

Question

Is WebStorm needed if you have a Rider license?

Answer

Rider includes most of the WebStorm functionality. However, there might be some bumps like the absence of some WebStorm templates: 

RIDER-7965 Add these Webstorm templates to Rider

It is worth having a glance at the issues existing: 

Existing Web-related issues

All in all, it is recommended to try coding In Rider within a trial period or in a non-commercial version to check if it fulfills your needs.