Add worksheet name max length to a constant

Close #163

2 files changed, 7 insertions, 3 deletions

diff --git a/lib/axlsx/util/constants.rb b/lib/axlsx/util/constants.rb
index 76db47bb..3f30216f 100644
--- a/lib/axlsx/util/constants.rb
+++ b/lib/axlsx/util/constants.rb
@@ -274,6 +274,9 @@ module Axlsx
   # cellXfs id for default date styling
   STYLE_DATE = 2
 
+  # worksheet maximum name length
+  WORKSHEET_MAX_NAME_LENGTH = 31
+
   # error messages RestrictionValidor
   ERR_RESTRICTION = "Invalid Data: %s. %s must be one of %s.".freeze
 
@@ -290,7 +293,7 @@ module Axlsx
   ERR_SHEET_NAME_EMPTY = "Your worksheet name is empty. Worksheet name can't be empty. Please assign name of your sheet or don't use name option at all.".freeze
 
   # error message for sheets that use a name which is longer than 31 bytes
-  ERR_SHEET_NAME_TOO_LONG = "Your worksheet name '%s' is too long. Worksheet names must be 31 characters (bytes) or less".freeze
+  ERR_SHEET_NAME_TOO_LONG = "Your worksheet name '%s' is too long. Worksheet names must be #{WORKSHEET_MAX_NAME_LENGTH} characters (bytes) or less".freeze
 
   # error message for sheets that use a name which include invalid characters
   ERR_SHEET_NAME_CHARACTER_FORBIDDEN = "Your worksheet name '%s' contains a character which is not allowed by MS Excel and will cause repair warnings. Please change the name of your sheet.".freeze
diff --git a/lib/axlsx/workbook/worksheet/worksheet.rb b/lib/axlsx/workbook/worksheet/worksheet.rb
index d782fefe..b51e2c00 100644
--- a/lib/axlsx/workbook/worksheet/worksheet.rb
+++ b/lib/axlsx/workbook/worksheet/worksheet.rb
@@ -303,7 +303,8 @@ module Axlsx
     end
 
     # The name of the worksheet
-    # The name of a worksheet must be unique in the workbook, and must not exceed 31 characters
+    # The name of a worksheet must be unique in the workbook, and must not exceed the number
+    # of characters defined in Axlsx::WORKSHEET_MAX_NAME_LENGTH
     # @param [String] name
     def name=(name)
       validate_sheet_name name
@@ -684,7 +685,7 @@ module Axlsx
       # ignore first character (BOM) after encoding to utf16 because Excel does so, too.
       raise ArgumentError, (ERR_SHEET_NAME_EMPTY) if name.empty?
       character_length = name.encode("utf-16")[1..-1].encode("utf-16").bytesize / 2
-      raise ArgumentError, (ERR_SHEET_NAME_TOO_LONG % name) if character_length > 31
+      raise ArgumentError, (ERR_SHEET_NAME_TOO_LONG % name) if character_length > WORKSHEET_MAX_NAME_LENGTH
       raise ArgumentError, (ERR_SHEET_NAME_CHARACTER_FORBIDDEN % name) if '[]*/\?:'.chars.any? { |char| name.include? char }
       name = Axlsx::coder.encode(name)
       sheet_names = @workbook.worksheets.reject { |s| s == self }.map { |s| s.name }