Initial commit of modash

This was taken from github.com/lmika/gopkgs/fp

moslice/map.go

@@ -0,0 +1,33 @@
+package moslice
+
+// Map returns a new slice containing the elements of ts transformed by the passed in function.
+func Map[T, U any](ts []T, fn func(t T) U) (us []U) {
+	if ts == nil {
+		return nil
+	}
+
+	us = make([]U, len(ts))
+	for i, t := range ts {
+		us[i] = fn(t)
+	}
+	return us
+}
+
+// Map returns a new slice containing the elements of ts transformed by the passed in function, which
+// can either either a mapped value of U, or an error. If the mapping function returns an error, MapWithError
+// will return nil and the returned error.
+func MapWithError[T, U any](ts []T, fn func(t T) (U, error)) (us []U, err error) {
+	if ts == nil {
+		return nil, nil
+	}
+
+	us = make([]U, len(ts))
+	for i, t := range ts {
+		var e error
+		us[i], e = fn(t)
+		if e != nil {
+			return nil, e
+		}
+	}
+	return us, nil
+}