lookup

open fun <K, V> TMap<K, V>.lookup(k: K): V?

Lookup a value at the specific key k

import arrow.fx.stm.TMap
import arrow.fx.stm.atomically

suspend fun main() {
//sampleStart
val tmap = TMap.new<Int, String>()
val result = atomically {
tmap[1] = "Hello"
tmap[2] = "World"

tmap.lookup(1)
}
//sampleEnd
println("Result $result")
}

If the key is not present STM.lookup will not retry, instead it returns null.