`.let` is `map` on an `Option` `?.` notation is `...

# arrow

[CLOVIS]

.let is map on an Option

?. notation is flatMap on an Option

Your thoughts?

[streetsofboston]

Both ?.let and ?. can be a map or flatmap… depends 🙂

[streetsofboston]

val value: String? = ... 

val size = value?.length
val size = value?.let { it.length }

But, I agree, the ?.let lets you write a flatMap like expression easier:

string2?.let { string1?.concat(it) } 
or
string1?.let { it1 -> string2?.let { it1 + it } }

Still, not quite like flatMap 🙂