refactor: minor changes and fixes

internal/format/format.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"path/filepath"
+	"strings"
 
 	"gopkg.in/yaml.v3"
 )
@@ -92,11 +93,11 @@ func Unmarshal(data []byte, v any, inFormat DataFormat) error {
 // both the standard default format (JSON) and any command line
 // change to that provided by options.
 func DataFormatFromFileExt(path string, defaultFmt DataFormat) DataFormat {
-	switch filepath.Ext(path) {
-	case ".json", ".JSON":
+	switch strings.TrimLeft(strings.ToLower(filepath.Ext(path)), ".") {
+	case JSON.String():
 		// The file is a JSON file
 		return JSON
-	case ".yaml", ".yml", ".YAML", ".YML":
+	case YAML.String(), "yml":
 		// The file is a YAML file
 		return YAML
 	}

internal/kwargs/kwargs.go

@@ -5,15 +5,28 @@ import (
 	"fmt"
 
 	"git.towk2.me/towk/makeshift/internal/format"
+	"github.com/rs/zerolog/log"
 )
 
 const RESERVED_KEY = "kwargs"
 
 type KWArgs map[string]any
 
+func New() KWArgs {
+	return KWArgs{}
+}
+
 func (kw KWArgs) String() string {
-	b, _ := json.Marshal(kw)
-	return string(b)
+	return string(kw.Bytes())
+}
+
+func (kw KWArgs) Bytes() []byte {
+	b, err := json.Marshal(kw)
+	if err != nil {
+		log.Error().Err(err).Msg("failed to marshal kwargs")
+		return []byte("{}")
+	}
+	return b
 }
 
 func (kw *KWArgs) Set(v string /* should be JSON object*/) error {