What is the idiomatic way to do something when an Option is either None, or the inner value meets some condition?

//        in None case
//             │       in Some(_) case
//            ┌┴─┐  ┌───────────────────┐    
if foo.map_or(true, |foo_val| foo_val < 5) {
    // ...
}

For more information see Option::map_or.