Add data command

cmd/config.go

@@ -36,6 +36,7 @@ type Config struct {
 	Data             map[string]interface{}
 	funcs            template.FuncMap
 	add              addCommandConfig
+	data             dataCommandConfig
 	dump             dumpCommandConfig
 	edit             editCommandConfig
 	_import          importCommandConfig

cmd/data.go

@@ -0,0 +1,39 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/spf13/cobra"
+	vfs "github.com/twpayne/go-vfs"
+)
+
+type dataCommandConfig struct {
+	format string
+}
+
+var dataCommand = &cobra.Command{
+	Use:   "data",
+	Short: "Write the template data to stdout",
+	RunE:  makeRunE(config.runDataCommand),
+}
+
+func init() {
+	rootCommand.AddCommand(dataCommand)
+
+	persistentFlags := dataCommand.PersistentFlags()
+	persistentFlags.StringVarP(&config.data.format, "format", "f", "json", "format (JSON or YAML)")
+}
+
+func (c *Config) runDataCommand(fs vfs.FS, args []string) error {
+	format, ok := formatMap[strings.ToLower(c.data.format)]
+	if !ok {
+		return fmt.Errorf("unknown format: %s", c.data.format)
+	}
+	ts, err := c.getTargetState(fs)
+	if err != nil {
+		return err
+	}
+	return format(os.Stdout, ts.Data)
+}