diff --git a/lib/base62.rb b/lib/base62.rb
index 84f9fbf23c8..bec48359aa9 100644
--- a/lib/base62.rb
+++ b/lib/base62.rb
@@ -1,9 +1,9 @@
 # Modified version of: https://github.com/steventen/base62-rb
 
 module Base62
-  KEYS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".freeze
-  KEYS_HASH = KEYS.each_char.with_index.inject({}) { |h, (k, v)| h[k] = v; h }
-  BASE = KEYS.length
+  KEYS ||= "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".freeze
+  KEYS_HASH ||= KEYS.each_char.with_index.to_h
+  BASE ||= KEYS.length
 
   # Encodes base10 (decimal) number to base62 string.
   def self.encode(num)