refactored for maintainability

internal/db/isunique.go

@@ -0,0 +1,19 @@
+package db
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	"github.com/uptrace/bun"
+)
+
+func IsUnique(ctx context.Context, tx bun.Tx, model any, field, value string) (bool, error) {
+	count, err := tx.NewSelect().
+		Model(model).
+		Where("? = ?", bun.Ident(field), value).
+		Count(ctx)
+	if err != nil {
+		return false, errors.Wrap(err, "tx.NewSelect")
+	}
+	return count == 0, nil
+}