Extract id generation to own file

file.go

@@ -40,38 +40,6 @@ type Block struct {
 	Parent   string
 }
 
-type ID struct {
-	StrID  string
-	WasInt bool
-}
-
-func (id *ID) UnmarshalJSON(data []byte) error {
-	var intID int
-	err := json.Unmarshal(data, &intID)
-	if err == nil {
-		*id = ID{strconv.FormatInt(int64(intID), 10), true}
-		return nil
-	}
-
-	var strID string
-	err = json.Unmarshal(data, &strID)
-	if err == nil {
-		*id = ID{strID, false}
-		return nil
-	}
-
-	return fmt.Errorf("could not unmarshal %q as an int or string", data)
-}
-
-func (id *ID) NewID() string {
-	if id.WasInt {
-		l := time.Now().UnixNano()
-		r := rand.Uint64()
-		return fmt.Sprintf("_%d_%d", l, r)
-	} else {
-		return id.StrID
-	}
-}
 
 // ListItemV2 is way to convert from old structure to new structure
 type ListItemV2 struct {

id.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"math/rand"
+	"strconv"
+	"time"
+)
+
+type ID struct {
+	StrID  string
+	WasInt bool
+}
+
+func (id *ID) UnmarshalJSON(data []byte) error {
+	var intID int
+	err := json.Unmarshal(data, &intID)
+	if err == nil {
+		*id = ID{strconv.FormatInt(int64(intID), 10), true}
+		return nil
+	}
+
+	var strID string
+	err = json.Unmarshal(data, &strID)
+	if err == nil {
+		*id = ID{strID, false}
+		return nil
+	}
+
+	return fmt.Errorf("could not unmarshal %q as an int or string", data)
+}
+
+func (id *ID) NewID() string {
+	if id.WasInt {
+		l := time.Now().UnixNano()
+		r := rand.Uint64()
+		return fmt.Sprintf("_%d_%d", l, r)
+	} else {
+		return id.StrID
+	}
+}