If project is small and will remain small, I would recommend to structure by type (Method 2: ng-book2)
app
|- components
| |- hero
| |- hero-list
| |- villain
| |- ...
|- services
| |- hero.service.ts
| |- ...
|- utils
|- shared
If project will grow you should structure your folders by domain (Method 3: mgechev/angular2-seed)
app
|- heroes
| |- hero
| |- hero-list
| |- hero.service.ts
|- villains
| |- villain
| |- ...
|- utils
|- shared
Better to Follow official docs.
https://angular.io/guide/styleguide#application-structure-and-ngmodules