added the generic Valid function

go.mod

@@ -1,6 +1,6 @@
 module gitea.sebastian-tobie.de/sebastian/generic
 
-go 1.18
+go 1.19
 
 require github.com/rs/zerolog v1.27.0
 

validators.go

@@ -0,0 +1,16 @@
+package generic
+
+// Valid returns true if the argument is not nil and can be converted to the type.
+// if additional validators are required they can be given as arguments
+func Valid[T any](item any, validator ...func(T) bool) (ok bool) {
+	if item != nil {
+		var v, ok = item.(T)
+		if len(validator) != 0 {
+			for _, vali := range validator {
+				ok = ok && vali(v)
+			}
+		}
+		return ok
+	}
+	return false
+}