Rollup

rollUp() is particularly useful in the context of organizational hierarchy as it summarizes hierarchical information more efficiently than using node.d

It can be used to calculate the sum, average, count, maximum, or minimum of the property values for a node and its descendants

It takes the generic form rollUp(aggregator, property)

Rollup Sum

The simple use of rollup is to aggregate a property for a node and its descendants

An example would be to calculate total salary of a team

Use rollup and define the aggregator and the property

node.rollUp("sum", "currentSalary")

Rollup excluding self

By default rollUp() includes the current node (its self)

If you want the expression to exclude the current node then you can add an argument to the rollUp() to "exclude self"

node.rollUp("sum", "currentSalary", { includeSelf: false })

Rollup with filters

If you have any filters applied, rollup() will perform calculations on the filtered subset of your data

To do roll-up calculations on the unfiltered data, allrollUp() should be used in the expression, instead of rollUp()

node.allrollUp("sum", "currentsalary")`

Rollup other aggregators

rollup() can be used with any of the Aggregator Functions with sum being replaced with avg, cnt, max, min to perform other operations depending on the situation.

To calculate the highest salary within a team

node.rollUp("max", "currentSalary")

Rollup with a lambda

rollup() can be used with a Lambda expression to test for a condition being met

An example would be to calculate total salary of a team, but only of managers (those who have at least one direct report)

The lambda expression can be used which tests if each node is a manager node._is_leaf == false

node.rollUp("sum", n => (n._is_leaf == false ? n.currentsalary : 0))

i.e. for the target node the expression tests if the node is not a leaf, if the node passes the test the current salary is used otherwise the value of 0 is used