# Bio: router component structure
## 0.0.0.2021
### 5.1
```ts
// ./Router.bio
import component { Counter } from './Counter.bio';
import component { Route404 } from './404.bio';
export router
// ./App.bio
import component { Router } from './Router.bio';
export app
```
### 5.1
```ts
import component { Counter } from './Counter.bio';
import component { Route404 } from './404.bio';
export router {...}}
@void doThingsBeforeEnter={() => {...}}
@void doThings={() => {...}}>
```