Options

Color theme preset.

Available Options:

• light (default)
• dark

Width of the chart. Accepts a pixel number or a CSS string.

Height of the chart. Accepts a pixel number or a CSS string.

Arbitrary CSS injected onto the root container element.

Initial zoom level expressed as pixels per day. Continuous: the timeline header automatically picks calendar tiers (year, quarter, month, week, day, halfday, hour, minute) based on the current value. Bounds are clamped to roughly [0.25, 1280] px/day.

Reference values calibrated against the legacy presets:

• Year ≈ 0.5
• Quarter ≈ 1.6
• Month ≈ 4.9
• Week ≈ 25.7
• Day = 80

When omitted, the chart auto-fits the full data range into the visible timeline area on first render. Supply an explicit value (or use the toolbar zoom controls) to take control.

Background color of the whole chart container.

Background color of the timeline and task-list header row.

Color of the cell and row divider lines.

Border color for all cells in the task table and timeline grid.

CSS border-width for all cell lines.

Whether to draw vertical lines between timeline columns. Set to false for a cleaner aesthetic that keeps only the horizontal row dividers.

Available Options:

• true (default)
• false

dayjs-compatible format string used to parse startTime / endTime values. Include time tokens (e.g. 'YYYY-MM-DD HH:mm') to enable sub-day scheduling; end-times are then treated as exclusive timestamps and inline editors switch to datetime-local inputs.

Initial pixel width of the task-list panel.

Allow the task-list panel to be resized by dragging the divider.

Show the export button in the toolbar. The format it produces is set by exportFormat.

Format the toolbar export button produces. Any format is also available programmatically through gantt.exportChart(format).

Available Options:

• svg (default): vector output
• png: rasterized image
• pdf: single-page, image-based, dependency-free

Size each task-list column to fit its header title and widest cell content, growing the task-list panel (never below tasksContainerWidth) so nothing is clipped. flexGrow still distributes any extra width, minWidth acts as a floor, and maxWidth (per column) as the ceiling. Set false to distribute the panel width purely by flexGrow.

Available Options:

• true (default)
• false

Allow task-list columns to be resized by dragging the handle at the trailing edge of a column header. A resized column is pinned to its chosen pixel width and the others absorb the remaining space. Double-click a handle to reset that column to auto width. Opt a single column out with columnConfig[].resizable: false.

Available Options:

• true (default)
• false

Allow columns to be reordered by dragging a column header left or right onto another column. A vertical drop indicator shows the insertion point. The new order is captured by getState() / setState() and emitted as a columnReorder event.

Available Options:

• true (default)
• false

Initial sort applied to the task list, as one SortCriterion or an array of them. Sorting is hierarchy-preserving: siblings reorder within each parent and the tree is never flattened. With multiple criteria the first key wins and ties break on the next. Pass [] for natural (input) order. See the Sorting and Filtering guide.

sortBy: { key: ColumnKey.Name, direction: 'asc' }
sortBy: [{ key: ColumnKey.Progress, direction: 'desc' }, { key: ColumnKey.Name }]

Column to sort by. A ColumnKey value for built-in columns or a custom column id.

Sort direction for this criterion.

Available Options:

• asc (default)
• desc

Initial predicate filter run against each task. A task is kept when it matches or has a matching descendant, so ancestors of matches stay visible. View-only: it changes which rows render, never the tree, WBS, or task data.

filterBy: (task) => task.progress < 100

Initial structured filter for the advanced filter builder: a FilterRuleSet of conditions combined with 'all' (AND) or 'any' (OR). Takes precedence over filterBy when both are set.

filterRules: {
  match: 'all',
  rules: [{ field: 'progress', operator: 'lt', value: 100 }],
}

How the rules combine.

Available Options:

• all: every rule must match (AND)
• any: at least one rule must match (OR)

The conditions to evaluate. An empty list means no filter.

Column key whose value is tested, either a ColumnKey or a custom column id.

Comparison operator applied to the field value.

Available Options:

• contains
• notContains
• equals
• notEquals
• startsWith
• endsWith
• gt
• gte
• lt
• lte
• before
• after
• on
• isEmpty
• notEmpty

Operand compared against the field: a number for number columns, a YYYY-MM-DD string for date columns, free text otherwise. Ignored by isEmpty and notEmpty.

Show a quick-filter search box in the toolbar that matches task fields as the user types.

Available Options:

• false (default)
• true

Fine-tune the quick filter. placeholder sets the input text (falls back to the localized quickFilterPlaceholder message), fields lists the task string fields matched (default ['name']), and caseSensitive controls case matching (default false).

quickFilter: { placeholder: 'Find a task', fields: ['name'], caseSensitive: false }

Placeholder text for the search input. Falls back to the localized quickFilterPlaceholder message when omitted.

Task string fields matched against the query.

Match the query case-sensitively.

Available Options:

• false (default)
• true

Show the advanced filter builder in the toolbar: a "Filter" button that opens a popover for composing field / operator / value conditions combined with All (AND) or Any (OR). Drives the same view-only filter as gantt.setFilterRules().

Available Options:

• false (default)
• true

Initial grouping applied to the task list, as a column key or a GroupCriterion. When set, the parent/child tree is suspended and every task appears flat under a collapsible group header. Clearing it restores the prior hierarchy. See the Row Grouping guide.

groupBy: ColumnKey.Progress
groupBy: { field: 'status', label: (v) => `Status: ${v}`, direction: 'desc' }

Allow drawing a new task by dragging across empty timeline space. On release a task is created with the swept range snapped to snapUnit / snapValue. A preview bar follows the cursor, a plain click creates nothing, and Escape cancels mid-drag. Existing bars stay draggable and resizable. Creation runs through the beforeTaskAdd veto hook and is undoable.

Available Options:

• false (default)
• true

Show a chevron at the edge of any row whose bar is scrolled out of the visible timeline window; clicking it jumps the bar into view. Opt-in from 3.15.0 onward (previously true). gantt.scrollToTask() works regardless of this setting.

Available Options:

• false (default)
• true

Clicking a task-list row scrolls that task's bar into view (nearest-edge, both horizontal and vertical), the same as calling gantt.scrollToTask(). Composes with enableSelection, so a single click both selects the row and reveals its bar. Clicks on the selection checkbox, the toggle chevron, and active inline-edit inputs are ignored.

Available Options:

• false (default)
• true

Persist and restore the UI view state (zoom, scroll, sort, filter, collapse, selection, manual column widths, and column order) via localStorage. Pass true for the default key ('apexgantt-state'), or an object { key } to set a custom key. Restored on the first render() and saved (debounced) on every view change. The state is also available programmatically through gantt.getState() / gantt.setState(). See the Saving and Restoring State guide.

persistState: true
persistState: { key: 'project-42-gantt' }

Color of dependency arrows between tasks.

Default background fill color for task bars. Theme-aware: a different default applies in the dark theme.

CSS border-radius applied to task bars.

Top and bottom margin inside each row for the task bar in pixels.

Text color rendered inside task bars.

Fill color for summary (group) bars. Renders distinct from regular task bars to make the parent/child hierarchy visually obvious. Theme-aware.

Fill color for milestone diamonds. Theme-aware.

Per-task bar label. By default the task name renders to the right of the bar so narrow bars don't clip their text. Set position: 'inside' to render centered inside the bar, 'auto' to pick automatically based on bar width, or supply render to compose names with chips, icons, or owner info.

barLabel: {
  position: 'auto',
  render: (task) => `<span>${task.name} · ${task.progress}%</span>`,
}

Where to render the label relative to the bar.

Available Options:

• right (default): rendered immediately to the right of the bar; always visible regardless of bar width
• inside: centered inside the bar; clipped when the bar is narrower than the text
• left: rendered immediately to the left of the bar
• auto: inside when the label fits, otherwise right

Task field whose value populates the label when render is not set.

Custom renderer for the bar label. Receives the resolved task and returns an HTML string (assigned via innerHTML, so escape user input yourself) or an HTMLElement. Returning null or undefined falls back to rendering barLabel.field.

Extra CSS class added to the label element.

Pixels of empty space added to the start of the timeline so left-side labels have room to render without being hidden behind the task-list panel. Auto-defaults to 120 when position is 'left', and 0 otherwise. Set explicitly to 0 to disable the padding.

Alternating row background colors. The pattern cycles automatically.

Height of each task row in pixels.

Allow tasks to be reordered by dragging rows in the task list.

Show the inline task-edit form when a task row is clicked.

Allow editing task fields directly in task-list cells. When true, double-clicking a name, startTime, endTime, duration, or progress cell swaps the cell for an input: commit with Enter or blur, cancel with Escape. Summary rows, milestones, and empty rows are not editable. Auto-enabled when enableTaskEdit is true unless explicitly set to false.

Available Options:

• false (default)
• true

Allow task bars to be resized by dragging their handles.

Allow editing task progress by dragging the small handle at the bottom of the bar. The handle becomes visible on bar hover and snaps to whole percent on commit. Emits a taskProgressChanged event.

Available Options:

• true (default)
• false

Enable keyboard shortcuts for task editing when the task-list panel has focus: Delete / Backspace deletes the focused row (cascade 'children'), Tab / Shift+Tab indent / outdent in the tree. Off by default. See the Inline Editing guide.

Show built-in + Add Task, Delete, and Undo/Redo buttons in the toolbar. The delete button acts on the current selection, so pair it with enableSelection: true. Off by default.

Show a built-in right-click context menu on task bars and task-list rows (Edit, Add child / sibling, Indent, Outdent, Delete). Entries are gated by capability. Off by default.

Show a single-line + Add task row at the bottom of the task list that inserts a new root-level task on click. Disabled automatically once row virtualization kicks in (dataset >= 50 rows). Off by default.

Granularity at which task drag, resize, and inline edits snap. Affects data updates only: the timeline header tier follows pixelsPerDay independently. Use 'hour' or 'minute' together with snapValue for sub-day scheduling; end-times are treated as exclusive timestamps when inputDateFormat includes time tokens.

Available Options:

• day (default)
• hour
• minute

Multiplier applied to snapUnit. Examples: snapUnit: 'minute', snapValue: 15 snaps to 15-minute increments; snapUnit: 'hour', snapValue: 6 snaps to 6-hour increments.

Enable row selection (click, Ctrl+Click, Shift+Click, keyboard).

Show a checkbox column for multi-select. Only applies when enableSelection is true.

When true, calculates and highlights the critical path through dependent tasks.

Fill color for task bars on the critical path (requires enableCriticalPath: true).

Stroke color for dependency arrows on the critical path.

When true, summary (parent) rows display thin rollup markers below the summary bar at each leaf descendant's date range, a glance-able overview of children that stays visible even when the parent is collapsed.

Available Options:

• false (default)
• true

Baseline options. When enabled is true, tasks with a baseline field render a thin bar below the actual bar to show schedule variance.

Whether to render baseline bars below actual bars.

Color of the baseline bar. When striped is true this paints the stripes; otherwise it fills the whole bar.

Fill the baseline bar with diagonal stripes that alternate between color and stripeColor, instead of a flat fill. Default true.

Color of the gaps between stripes. Only used when striped is true. Default '#FFFFFF'.

Width in pixels of each stripe band when striped is true. Larger values produce thicker stripes. Default 3.

Angle in degrees of the stripes when striped is true. Default 45.

Visual and interaction options for dependency arrows. Tune cornerRadius for tighter or looser joints, set hitWidth to add an invisible thicker target zone for hover/click on thin strokes, and use tooltipTemplate / classBuilder for per-arrow content and styling.

dependencies: {
  cornerRadius: 6,
  hitWidth: 12,
  classBuilder: (ctx) => ctx.fromTask.team !== ctx.toTask.team ? 'cross-team' : '',
  tooltipTemplate: (ctx) => `<b>${ctx.fromTask.name}</b> → <b>${ctx.toTask.name}</b>`,
}

Pixel radius for rounded joints on dependency arrows. 0 produces sharp 90° corners; larger values produce smoother arcs (clamped per-corner to half the shorter adjacent segment so an arc never overshoots).

Invisible hit-area thickness in pixels. When greater than 0, each arrow renders an additional transparent path of this width that captures pointer events, making the thin visible stroke easier to hover or click. Required for tooltipTemplate to fire.

Returns CSS class name(s) for each arrow. Receives a DependencyContext (fromTask, toTask, type, lag) and returns a class name string, an array of class names, or undefined. Use to tag arrows by relationship (cross-team, blocked, optional) and style them via custom CSS.

Returns an HTML string shown when the user hovers an arrow. Receives a DependencyContext (fromTask, toTask, type, lag). Requires a non-zero hitWidth so the hover hit area is large enough to register reliably.

Enables interactive editing of dependency arrows: hovering darkens the arrow and drag handles appear so users can rewire or delete links. Deletions go through the same undoable command path as removeDependency().

Whether a dependency may connect a summary task to one of its own descendants. Off by default because such links usually indicate a data error. Applies to interactive editing and the programmatic addDependency() / canAddDependency() paths.

Show a vertical crosshair line that follows the cursor across the timeline, with a label displaying the precise date or time at the pointer position.

Available Options:

• false (default)
• true

Color of the crosshair line and label background. Theme-aware.

Custom formatter for the crosshair label text. Receives the date under the cursor and the current sub-tier of the timeline header ('minute' | 'hour' | 'halfday' | 'day' | 'week' | 'month' | 'quarter' | 'year'). When omitted, the label auto-adapts to the active tier: coarse formats for week-and-above, HH:mm for halfday, hour, or minute tiers.

crosshairLabelFormat(date, tier) {
  return `${tier}: ${date.toISOString()}`;
}

Show a tooltip on task-bar hover.

HTML id for the tooltip container element.

Custom function returning an HTML string for the task tooltip.

tooltipTemplate(task, dateFormat) {
  return `
    <div>
      <div><strong>Task:</strong> ${task.name}</div>
      <div><strong>Start:</strong> ${task.startTime}</div>
      <div><strong>End:</strong> ${task.endTime}</div>
      <div><strong>Progress:</strong> ${task.progress}%</div>
    </div>
  `;
}

Background color of the hover tooltip.

Border color of the hover tooltip.

Color for all text in the chart.

CSS font-family for the chart. Falls back to the page default when empty.

CSS font-size for the chart.

CSS font-weight for the chart.

Background color of annotation markers.

Border color of annotation markers.

SVG stroke-dasharray for annotation borders, e.g. [6, 3].

Border width of annotation markers in pixels.

Whether annotation lines are drawn horizontally or vertically.

Available Options:

• horizontal (default)
• vertical

When true, two vertical lines mark the project's earliest start and latest end across all rows. Auto-recomputes when tasks are added, removed, or rescheduled.

Available Options:

• false (default)
• true

Stroke color for the project-boundary lines. Falls back to annotationBorderColor when omitted.

Custom column definitions for the task-list panel. When omitted, all default columns are shown.

Column identifier. Use a ColumnKey value for built-ins ('name', 'startTime', 'endTime', 'duration', 'progress', 'progressRing', 'wbs', 'predecessors', 'successors', 'assignees', 'baselineStart', 'baselineEnd', 'baselineVariance') or any other string for a custom column paired with a render function.

Header label displayed at the top of the column.

CSS min-width for the column, e.g. '120px'. Acts as the column's preferred width when autoSizeColumns is on.

Upper bound for the auto-sized column width, e.g. '240px'. Caps how wide the column grows to fit content so one long value can't dominate the panel. Ignored when autoSizeColumns is off. Default '320px'.

CSS flex-grow factor for the column.

Whether the column is visible. Defaults to true.

Whether this column can be resized by dragging the handle at its header's trailing edge. Requires the resizableColumns option. Set false to lock a single column at its auto/configured width. Default true.

Custom cell renderer. Required for custom columns; ignored for built-in columns. Receives a context object (task, options, rowIndex, isSummary, isMilestone) and the cell element. Return an HTML string to set innerHTML, return void if you mounted DOM yourself, or return a cleanup function () => void that the library will invoke on row eviction, full re-render, and destroy(): required for framework adapters (React.createRoot().unmount(), Vue.app.unmount(), etc.).

Extracts the underlying value of the cell from the task. Used by sorting, filtering, and SVG export. Optional for built-in columns; for a custom column it is what makes the column sortable and filterable.

Whether the column participates in sorting (header click plus the sortBy option and gantt.sort()). Defaults to true for built-in value columns, false for the Wbs column, and true for a custom column only when an accessor or comparator is supplied.

Custom sort comparator for the column. Takes precedence over accessor-based comparison. Receives two tasks and returns a negative, zero, or positive number for ascending order; the active sort direction is applied on top. Stable: equal results fall back to natural (input) order.

Custom controls rendered in the toolbar alongside the built-in zoom and export buttons. Each item can be a ToolbarButton, ToolbarSelect, or ToolbarSeparator. Use position: 'left' to insert before the built-in controls (default is 'right').

aria-label for the task-list table, used by screen readers.

Localization, date-locale, and text-direction options. Defaults to { direction: 'ltr' }, which reproduces the pre-localization output. See the Localization and RTL guide for worked examples.

Text and layout direction.

Available Options:

• ltr (default): left-to-right
• rtl: mirrors the timeline horizontally (time flows right-to-left, the task list moves to the right) and sets dir="rtl" on the container
• auto: defers to the document or element's inherited direction

dayjs-compatible locale object used to format every date, month, and weekday in the timeline. Import one from dayjs/locale/* (e.g. import localeFr from 'dayjs/locale/fr') and pass it here. ApexGantt registers it on its own bundled dayjs instance, so the host does not need to import dayjs locales.

Locale identifier, e.g. 'fr' or 'en'.

Full weekday names, Sunday first.

Abbreviated weekday names, Sunday first.

Minimal weekday names, Sunday first.

Full month names, January first.

Abbreviated month names, January first.

Index of the first day of the week, where 0 is Sunday.

Week-of-year calculation rule: the day of January that the first week of the year must contain.

Named date-format tokens keyed by dayjs format name (e.g. LT, LL).

Templates for relative-time strings, keyed by dayjs unit (e.g. future, past, dd).

Function returning the AM/PM string for a given hour, minute, and lowercase flag.

Function returning the ordinal form of a number, e.g. 1 to 1st.

Overrides for the Gantt's generated strings. Accepts a partial set; unset keys keep their English defaults. Plain labels are strings; strings that embed runtime data are functions.

"Add task" toolbar button label.

"Delete selected" toolbar button label.

Undo toolbar button label.

Redo toolbar button label.

Export toolbar button label for the SVG format.

Export toolbar button label for the PNG format.

Export toolbar button label for the PDF format.

Placeholder for the built-in quick-filter search box.

Advanced filter builder toolbar button label.

Filter builder popover heading.

Filter builder match-mode label.

Filter builder match-all (AND) option label.

Filter builder match-any (OR) option label.

Filter builder add-condition button label.

Filter builder apply button label.

Filter builder clear button label.

Filter builder remove-condition button aria-label.

Filter builder empty-state text shown when no conditions exist.

Function returning the human-readable label for a comparison operator.

Group header label for tasks whose group value is empty.

Function returning the group header member-count label from the count, e.g. (3).

Alert shown when export cannot find the chart.

Generic export-failure alert.

Context-menu "Edit task" label.

Context-menu "Add child task" label.

Context-menu "Add sibling task" label.

Context-menu "Indent" label.

Context-menu "Outdent" label.

Context-menu delete label for a leaf task.

Context-menu delete label for a task with children.

Task-form name field label.

Task-form start-date field label.

Task-form end-date field label.

Task-form progress field label.

Task-form submit button label.

Function returning the edit-task dialog title from the task name.

Validation message shown when the start date is missing.

Validation message shown when the end date is missing.

Validation message shown when the end date is not after the start date.

Validation message shown when the task name is missing.

Validation message shown when progress is missing.

Validation message shown when progress falls outside 0 to 100.

Visible label on the inline add-task row.

Baseline tooltip "Baseline:" label.

Baseline tooltip "Start:" label.

Baseline tooltip "End:" label.

Function that builds a summary-bar aria-label from a context object (name, canToggle, collapsed).

Function that builds an interactive or read-only bar aria-label from a context object (name, start, end, and progress for read-only bars).

Function that builds the bar aria-valuetext for interactive bars from a context object (start, end, durationDays).

Function that builds the progress-handle aria-label from the task name.

Field-mapping config to parse non-standard task shapes without manual data transformation.

parsing: {
  id: 'task_id',
  name: 'title',
  startTime: 'start_date',
  endTime: 'end_date',
  progress: { key: 'pct_complete', transform: Number },
}

Path to the unique task identifier in the raw data object.

Path to the task display name in the raw data object.

Path to the task start date in the raw data object.

Path to the task end date in the raw data object.

Path to the task progress value in the raw data object.

Path to the task type ('task' or 'milestone') in the raw data object.

Path to the parent task ID in the raw data object.

Path to the dependency field in the raw data object.

Path to a per-task bar color override in the raw data object.

Path to a per-task row background color override in the raw data object.

Path to the collapsed state in the raw data object.

Task data array. Each item must satisfy TaskInput, or use parsing to map custom field names.

series: [
  {
    id: 'task-1',
    name: 'Design Phase',
    startTime: '01-01-2026',
    endTime: '01-15-2026',
    progress: 65,
  },
  {
    id: 'task-2',
    name: 'Development',
    startTime: '01-10-2026',
    endTime: '02-01-2026',
    parentId: 'task-1',
    progress: 30,
    dependency: 'task-1',
  },
]

Unique identifier for the task. Must be stable across renders.

Display name shown in the task list column and task bar.

Task start date string. Parsed using inputDateFormat.

Task end date string. Parsed using inputDateFormat. When omitted, the task renders as a milestone on startTime.

Completion percentage (0–100). Renders a filled progress portion inside the task bar.

Visual type of the task.

Available Options:

• task: renders a bar (default)
• milestone: renders a diamond marker

ID of the parent task. Nested tasks are rendered as children in the task list.

Dependency on another task. Accepts either a plain task ID string (treated as Finish-to-Start with 0 lag) or a full TaskDependency object for typed dependency with lag/lead support.

// Simple string dependency
dependency: 'task-2'

// Full dependency object
dependency: { taskId: 'task-2', type: 'FS', lag: 2 }

Override the task bar fill color for this specific task.

Override the row background color for this specific task row.

Baseline (planned) dates for comparison against actual dates. Rendered as a thin bar below the actual task bar when baseline.enabled is true.

Planned (baseline) start date of the task.

Planned (baseline) end date of the task.

Whether this task's child tasks are collapsed (hidden) in the task list.

When true (the default), a task with children renders as a summary (group) bar whose date range is automatically computed from the earliest start and latest end of all its descendants: the task's own startTime / endTime are ignored. Drag, resize, and progress edits are disabled on summary bars. Set to false to opt the parent out of the auto-derived summary bar and render it as a normal task bar instead.

People (or teams) assigned to this task. Consumed by the built-in renderers.avatars column renderer; ignored unless an avatar-style column is configured via columnConfig. Each Assignee carries name, optional avatarUrl, optional initials, and optional fallback color.

Worked spans of a split task. When two or more are provided, the task renders as separate bar pieces with gaps between them, and its startTime / endTime are derived from the segments (first start to last end). Omit, or provide fewer than two, for a normal contiguous task. Split a task at runtime via gantt.splitTask().

Array of annotation objects to overlay on the timeline.

annotations: [
  {
    x1: '01-15-2026',
    x2: '01-20-2026',
    label: { text: 'Sprint Review' },
  },
  {
    x1: '02-01-2026',
    label: { text: 'Deadline' },
  },
]

Start date of annotation.

End date of annotation. If present, draws a rect from x1 to x2. If null or omitted, only draws a line on x1.

Background color of this annotation. Overrides the global annotationBgColor.

Border color of this annotation. Overrides the global annotationBorderColor.

SVG stroke-dasharray for this annotation's border.

Border width of this annotation in pixels.

Label configuration for the annotation.

Label text for the annotation.

Font color for the annotation label.

Font family for the annotation label.

Font size for the annotation label.

Font weight for the annotation label.

Text orientation of the annotation label.

Available Options:

• horizontal
• vertical

Working-calendar configuration. When set, weekends and holidays drive duration math, summary aggregation, and timeline stripes. Absent means every day is a working day. See the Calendar and Working Days guide.

Weekdays that count as working days, where 0 is Sunday and 6 is Saturday. Default [1, 2, 3, 4, 5] (Mon–Fri).

Specific non-working dates, regardless of weekday. Each entry may be a date string, a Date, or { date, label } for a tooltipped holiday. Default [].

Render hatched bands over non-working timeline columns. Default true.

Optional function returning an HTML string shown when hovering a holiday stripe. Receives { date, label }.

Where a drag or resize lands when it hits a non-working day.

Available Options:

• next (default): snap forward to the next working day
• previous: snap backward to the previous working day
• allow: permit non-working start/end dates

Undo/redo history configuration. Every mutating call (drag, resize, inline/dialog edit, add, delete, move, dependency change) is recorded unless disabled. See the Undo and Redo guide.

When false, no commands are recorded and undo() / redo() are no-ops. Default true.

Maximum number of undo entries retained; older entries drop off the bottom (FIFO). Default 100.

Veto hook called immediately before a task is inserted via addTask(). Return false (or a promise resolving to false) to cancel the insertion. Useful for permissions or payload validation.

Veto hook called before any task update commits (drag, resize, progress drag, inline/dialog edit, or programmatic updateTask()). Return false to reject the change; a taskValidationError event fires and the chart reverts. See the Inline Editing guide.

Veto hook called before a task is re-parented via moveTask() or an indent/outdent. Return false to cancel the move.

Veto hook called before a task is removed via deleteTask(). Return false to cancel the deletion.

Veto hook called before a dependency is added or removed (interactively or via addDependency() / removeDependency()). Return false to reject the change.