3357171 fix, Introduced the following deprecation, in the edge case there are no words to count:
Deprecated function: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in Drupal\node_read_time\Calculate\ReadingTime->calculateReadingTime() (line 178 of modules/contrib/node_read_time/src/Calculate/ReadingTime.php).
Drupal\node_read_time\Calculate\ReadingTime->calculateReadingTime() (Line: 76)
Use node read time for instance with the computed field for a given content type, create a content with only title set and the deprecation is thrown.
Check that words property is not empty.
Fixed
1.0
Code
Thank you for reporting and fixing this. Added this to a new tag, so it is available now in 8.x-1.13
Automatically closed - issue fixed for 2 weeks with no activity.