A traditional way of handling backend data on a frontend is to feed it to services, controllers, components and the like. But when I started binding ES6 classes to backend data and all business logic went into classes, my components got much cleaner, and I got a lot of possibilities to handle and transform data inside classes. It was a big shift to make my frontend code cleaner and shorter. You just simply use Object.setPrototypeOf:

classes.mjs

export class User{
  get fullName(){
    return `${this.firstName} ${this.lastName}`;
  }
}

import { User } from './classes.mjs';
// fetch some users then attach the class
users.forEach(user => Object.setPrototypeOf(user, User.prototype));
// now you can use `user.fullName` anywhere

Another reason to bind class prototypes is performance. You don't need to create a new copy of data consisting of class instances, copy data into instance properties and so on and thus you save precious CPU time and memory providing faster user experience.