block by default so you can mount and unmount
block by default so you can mount and unmount

```js
{shouldBlock && <BlockHistory prompt={str}/>}
```

rafrex/react-router,OpenGov/react-router,DelvarWorld/react-router,goblortikus/react-router,DelvarWorld/react-router,OpenGov/react-router,asaf/react-router,reactjs/react-router,goblortikus/react-router,OpenGov/react-router,ReactTraining/react-router,ReactTraining/react-router,rafrex/react-router,d-oliveros/react-router,asaf/react-router,goblortikus/react-router,ReactTraining/react-router,reactjs/react-router,OpenGov/react-router,ReactTraining/react-router,goblortikus/react-router,rackt/react-router,rackt/react-router,d-oliveros/react-router,asaf/react-router