`npm test`
`ts-node index.ts` and server starts
output:
```
Express server started on port 3333
{
type: 'Block',
msgType: 'BLK_CONNECTED',
blockHash: '00000000000000000f39c3307a459d311213708d390b9d0e230437b1c5c00d5f',
blockHeight: 834086
}
{
type: 'Block',
msgType: 'BLK_FINALIZED',
blockHash: '00000000000000000f39c3307a459d311213708d390b9d0e230437b1c5c00d5f',
blockHeight: 834086
}
```