javascript – How to store user registration details in an angular file located in src/assets folder?

I’m developing a very simple Angular web app project. There is a Login component, Registration component, and DisplayDetails component. When a user registers using his/her email id, username and password and when he/she press the ‘Register’ button of the form, I want to store that information in original ‘src/assets/userDetails’ file that is deployed on the localhost (not in localStorage or sessionStorage of browser). So that when the user logIn again using credentials in any device or browser, I will send his/her login details to the login component and check if this credentials are present in the ‘src/assets/userDetails’ file or not. On the basis of the validation results I will route him/her to the DisplayDetails component, fetch his/her email and username from that ‘src/assets/userDetails’ file and display on the screen.

I have created all the components, but don’t know how to store registration information in the angular file and not in localStorage of browser. I know Node.js and Express at intermediate level, so I will understand any of your answers using Node.js and Express.
I know that I need a backend server kind of thing, but don’t have any idea of how to do that.

Any help is welcome.