```diff
+ const isValidScore = score =>
+   score >= 70
+
+ const isValidUser = user =>
+   user && user.length > 3

data.reduce((acc, rec) => {
  const { score, user } = rec

- if(score <= 70) {
+ if(!isValidScore(score)) {
    return acc.concat([])
  }

- if(!(user && user.length > 3)) {
+ if(!isValidUser(user)) {
-   return acc.concat([])
+   return acc.concat([ 'unknown' ])
  }

  return acc.concat([ user ])
}, [])
```