DHTMLX Planning Engine Documentation

TaskUpdate#

A partial edit of one existing task: its id plus the fields to change. It appears as an entry of tasks.update in a SchedulingChanges set. To add a task, send a TaskData record in tasks.add instead.

Each field has three states. Left out, it keeps its current value. A value sets it. null clears an optional field or puts a field that always has a value back to its default. Field names are snake_case, and a record must be a JSON object. Unknown fields are ignored, so an entry of ScheduleResult.updates can be sent back as a TaskUpdate as it is. See Wire format.

Fields#

Field Type Required Default Description
id Id yes - Id of the task to change
parent Id | null no unchanged New parent summary. null, "" and a value equal to config.root_id move the task to the top level
start_date DateValue | null no unchanged New start date. null clears it
end_date DateValue | null no unchanged New end date. null clears it
duration number | null no unchanged New working time in the task's duration_unit. null clears it
constraint_type ConstraintType | "" | null no unchanged "asap", "alap", "snet", "snlt", "fnet", "fnlt", "mso" or "mfo". "" and null remove the constraint
constraint_date DateValue | null no unchanged Date of a dated constraint. null clears it
auto_scheduling boolean | null no unchanged false fixes the task. null resets it to true
unscheduled boolean | null no unchanged true takes the task and its descendants out of the plan. null resets it to false
progress number | null no unchanged Completion from 0 to 1. null resets it to 0
calendar_id Id | null no unchanged Calendar the task works on. null clears it, so the default calendar applies (or the inherited one with calendar_mode: "task-inherited")
priority number | null no unchanged Leveling priority, a whole number from 0 to 1000. null resets it to 500
leveling_delay number | null no unchanged Elapsed time before the task's driven start, in the task's duration_unit. null resets it to 0
pauses Pause[] | null no unchanged Replaces the whole list of leveling splits. [] and null remove every pause

type and duration_unit aren't fields of TaskUpdate. Sent in an update, they're ignored like any unknown field. See What change sets can't do.

Which of start_date, end_date and duration an update keeps and which it derives is described in Which dates a task update keeps. An update without dates keeps the stored start and duration, unless it changes pauses or leveling_delay. See Delays and pauses.

Note

An unknown constraint_type, a priority outside 0..1000 or an invalid date fails the whole call with a validation error that has no path. In apply, this means no operation from that change set is applied. Other invalid values reject only this update. It's listed in ApplyReport.rejected.

Used by#

Example#

A drag, a resize, a new constraint, a reparent and a leveling reset:

[
  { "id": "design", "start_date": "2026-08-12 08:00" },
  { "id": "build", "duration": 6 },
  { "id": "review", "constraint_type": "snet", "constraint_date": "2026-08-20 08:00" },
  { "id": "docs", "parent": "phase2" },
  { "id": "test", "leveling_delay": 0, "pauses": [] }
]