@cheng-cli
Maybe not a direct answer to your question, but you can also use calendar .ics files for displaying holidays (with the default calendar module of mm), see links:
https://github.com/MichMich/MagicMirror/tree/master/modules/default/calendar
https://www.calendarlabs.com/online-calendar/2019-calendar/
AxLED
A New Chapter for MagicMirror: The Community Takes the Lead
Read the statement by Michael Teeuw here.
Read the statement by Michael Teeuw here.
C