Tasks

A task is the fundamental unit of a FluxGantt chart. You describe tasks with a TaskInput when constructing the chart (or when calling addTask); the store stamps the missing bookkeeping fields and hands you back a full Task.

`TaskInput` — what you provide

import { toTaskId } from '@fluxgantt/core';
import type { TaskInput } from '@fluxgantt/core';
 
const input: TaskInput = {
  id: toTaskId('build'),   // optional — auto-generated when omitted
  name: 'Build',
  start: '2026-08-05',     // DateInput: ISO string | Date | Temporal.PlainDate | Temporal.ZonedDateTime
  end: '2026-08-10',
  progress: 0.6,           // required, 0..1
  type: 'task',            // required: 'task' | 'summary' | 'milestone' | 'project'
};

TaskInput is Omit<Task, 'id' | 'createdAt' | 'updatedAt'> & { id?: TaskId }. That means:

name, start, end, progress, type are required. There is no default for type or progress — you supply them on every task (a milestone still needs progress and a type: 'milestone').
id is optional. Omit it and the store generates a task-<uuid>. Supply it via toTaskId('build') so you can reference the task later (in dependencies, getTask, etc.).

Optional fields

Field	Type	Notes
`id`	`TaskId`	Auto-generated when omitted. Brand a string with `toTaskId`.
`duration`	`number`	Working hours. Derived from `start`/`end` when omitted.
`priority`	`number`	Lower = higher priority (used by Pro resource leveling).
`parent`	`TaskId`	Groups this task under a summary/parent — see Hierarchy.
`constraint`	`TaskConstraint`	A scheduling constraint, discriminated by `kind`.
`notes`	`string`	Free-form text. Treated as untrusted when rendered.
`color`	`string`	Whitelist-validated (valid CSS color) before it reaches the DOM.
`meta`	`Record<string, unknown>`	Free-form user data. Untrusted when displayed.

`Task` — what you get back

addTask (and the getters) return a full Task, which adds the store-managed fields:

const task = gantt.addTask(input);
task.id;        // TaskId (branded)
task.createdAt; // Date
task.updatedAt; // Date

Task kinds

type: TaskKind is one of:

task — a normal bar.
milestone — a zero-duration marker (rendered as a diamond); use equal start/end.
summary — a roll-up bar spanning its children (see Hierarchy).
project — the top-level roll-up.

Branded IDs

TaskId is string & { readonly __brand: 'TaskId' }. A plain string is not assignable to it, which is what stops you passing a DependencyId (or an arbitrary string) where a TaskId belongs. Create one at the boundary with toTaskId(string) — you never write as TaskId.

import { toTaskId } from '@fluxgantt/core';
const id = toTaskId('build'); // TaskId

Mutating tasks

All of these return the updated Task and emit the matching event:

gantt.addTask(input);                       // → task:added
gantt.updateTask(id, { name: 'Rebuild' });  // → task:* per changed field
gantt.moveTask(id, '2026-08-06');           // → task:moved
gantt.resizeTask(id, 24);                    // 24 working hours → task:resized
gantt.setProgress(id, 0.75);                 // → task:progressed
gantt.removeTask(id);                         // → task:removed (cascades descendants)

See the API Reference for full signatures.