refactor: push commands in to cmd and ev to root as library

pkg/slice/slice.go

@@ -0,0 +1,35 @@
+package slice
+
+// FilterType returns a subset that matches the type.
+func FilterType[T any](in ...any) []T {
+	lis := make([]T, 0, len(in))
+	for _, u := range in {
+		if t, ok := u.(T); ok {
+			lis = append(lis, t)
+		}
+	}
+	return lis
+}
+
+// Find returns the first of type found. or false if not found.
+func Find[T any](in ...any) (T, bool) {
+	return First(FilterType[T](in...)...)
+}
+
+// First returns the first element in a slice.
+func First[T any](in ...T) (T, bool) {
+	if len(in) == 0 {
+		var zero T
+		return zero, false
+	}
+	return in[0], true
+}
+
+// Map applys func to each element s and returns results as slice.
+func Map[T, U any](s []T, f func(T) U) []U {
+	r := make([]U, len(s))
+	for i, v := range s {
+		r[i] = f(v)
+	}
+	return r
+}