Code review suggestions for list command

internal/playlist/list.go

@@ -3,27 +3,39 @@ package playlist
 import (
 	"fmt"
 	"spotify/internal"
+	"strings"
 
+	"github.com/brianstrauch/spotify"
 	"github.com/spf13/cobra"
 )
 
 func NewListCommand() *cobra.Command {
 	return &cobra.Command{
-		Use:     "list",
-		Short:   "List playlists.",
+		Use:   "list",
+		Short: "List playlists.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			api, err := internal.Authenticate()
 			if err != nil {
 				return err
 			}
-			playlists, err := api.GetPlaylists()
+			output, err := List(api)
 			if err != nil {
 				return err
 			}
-			for _, pl := range playlists {
-				fmt.Println(pl.Name)
-			}
+			fmt.Print(output)
 			return nil
 		},
 	}
 }
+
+func List(api *spotify.API) (string, error) {
+	playlists, err := api.GetPlaylists()
+	if err != nil {
+		return "", err
+	}
+	var builder strings.Builder
+	for _, pl := range playlists {
+		builder.WriteString(fmt.Sprintln(pl.Name))
+	}
+	return builder.String(), nil
+}