DHTMLX Planning Engine Documentation

SchedulingChanges#

One set of edits to a live Project: tasks, links, resources and assignments to add, update or remove. Build it as a plain object and pass it to Project#apply or Project#preview, or put it in a Candidate. Project#suggestAssignments returns one in result.changes.

Fields#

Field Type Default Description
baselineId string none Baseline token the edits were made against. Omitted: no check. Set: it must name the project's current baseline, or the call throws ProjectError "stale-baseline".
tasks bucket of TaskData / TaskUpdate empty Tasks to add, update or remove by id.
links bucket of LinkAdd / LinkUpdate empty Links to add, update or remove by id. A LinkAdd without an id gets a generated one.
resources bucket of ResourceData / ResourceUpdate empty Resources to add, update or remove by id.
assignments bucket of AssignmentData / AssignmentUpdate empty Assignments to add, update or remove by id.

Each bucket is an object with three optional arrays:

Field Type Default Description
add record array [] New records, in the bucket's add type.
update record array [] Partial records: id is required, every other field is optional.
remove Id[] [] Ids of the records to remove.

A bucket set to null reads as empty. null in place of one of its arrays is a parse error. Unknown keys on the change set or on a bucket throw an InputError; unknown fields inside the records are ignored, so objects with extra UI fields can be passed as they are.

There's no calendars bucket. Calendars change only through a full solve(data).

Take the token for baselineId from the latest solve result (ScheduleResult baselineId). Tokens are opaque: don't compare them across runs.

Operation order#

Operations run in a fixed order, not in the order the keys appear. Kinds run in the order tasks, links, resources, assignments. Within a kind:

Kind Order
tasks remove, add, update
links remove, update, add
resources remove, add, update
assignments remove, update, add

Within an array, records run in array order. Each operation is named by its bucket and index, such as "tasks.update[0]", in the path of the ApplyReport entries.

Used by#

Example#

Move task 1, link it to task 2 and check the edit against the current baseline.

// solved: the result of the latest project.solve(...)
const changes = {
  baselineId: solved.baselineId,
  tasks: { update: [{ id: 1, start_date: "2026-08-12 08:00" }] },
  links: { add: [{ source: 1, target: 2, type: "fs" }] },
};