Start, end date calculation

Using the 04_customization/15_baselines.html sample, dates were added in addition to the start and end dates. The added date can be modified like start and end date. I want to know how to calculate the date of parent and child relationship in the same way as start_date and end_date in tree format for added date.

Hello Seungmin,
Gantt doesn’t watch custom properties, so, there is no built-in way to update the custom dates of a parent task, depending on its children. You need to manually implement a custom solution by using Gantt API and Javascript.

The following example can help you to start: