add methods to convert resmap to&from rnodes

api/resmap/factory.go

@@ -9,6 +9,7 @@ import (
 	"sigs.k8s.io/kustomize/api/internal/kusterr"
 	"sigs.k8s.io/kustomize/api/resource"
 	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
 // Merginator merges resources.
@@ -148,3 +149,20 @@ func newResMapFromResourceSlice(
 	}
 	return result, nil
 }
+
+// NewResMapFromRNodeSlice returns a ResMap from a slice of RNodes
+func (rmF *Factory) NewResMapFromRNodeSlice(rnodes []*yaml.RNode) (ResMap, error) {
+	var resources []*resource.Resource
+	for _, rnode := range rnodes {
+		s, err := rnode.String()
+		if err != nil {
+			return nil, err
+		}
+		r, err := rmF.resF.FromBytes([]byte(s))
+		if err != nil {
+			return nil, err
+		}
+		resources = append(resources, r)
+	}
+	return newResMapFromResourceSlice(resources)
+}