Enhancement to calculate additional metrics (numeric values) from the data stream visible to a business process. The “matchExpr” determines which datapoints will be evaluated and “evaluateExpr” determines the new value of the metric.
For example to calculate the number of user click events during a business process you could use the following config:
matchExpr: (factType.name == "UX_EVENT" && eventType.category == "HTTP:Click")
evaluateExpr: metricValue + 1 (explicit return is un-needed in this case because the result of the last statement is the implicit return value)