Explicación: Servicios http

9.2. Ruta nueva: /posts/:id/edit

Después de posts/new y antes de posts/:id:

{ path: 'posts/:id/edit', component: PostFormComponent },

{ path: 'posts', component: PostsListComponent },
{ path: 'posts/new', component: PostFormComponent },
{ path: 'posts/:id/edit', component: PostFormComponent },
{ path: 'posts/:id', component: PostDetailComponent },