Specifying the 'or' operator in event expressions
The or operator lets you specify event expressions where a variety of event patterns could lead to a successful match. It effectively evaluates two event templates (or entire nested event expressions) simultaneously and returns true when either of them becomes true.
For example,
on A() or B() executeAction();
means that either A or B need to be detected to match. That is, the occurrence of one of the operand expressions (an A or a B) is enough for the event listener to trigger.