@gantryjs/core

Framework-free core of the Gantry Gantt chart: domain types, timeline math, tree helpers and critical-path computation. No DOM, no framework — runs in browsers, Node, workers and SSR. No runtime dependencies.

You usually don't install this directly: it powers @gantryjs/angular (Angular) and @gantryjs/vanilla (Web Component, used by the React, Vue and Svelte bindings), and every binding re-exports it. Use it on its own to compute schedules server-side or to build your own renderer.

Install

npm i @gantryjs/core

What's inside

| Area | Exports | | ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Types | GanttTask, GanttDependency, GanttOptions, GanttTheme, ColumnDef, GanttAnnotation, TaskDragEvent, TaskResizeEvent, RetryEvent, … and ViewMode, TaskType, DependencyType (as const objects with same-name types: ViewMode.Week works as a value and as a type) | | Timeline math | dateToPixel, pixelToDate, calendarDays, addDays, formatDate, durationLabel | | Render model | resolveConfig (every option default), buildTimeline, computeRowGeometries, computeBarVisual / hitTestBar, computeArrowVisual, computeMarkerLane, DragSession, formatDragReadout, wheelZoom / fitZoomLevel / anchoredScrollLeft, LightTheme / DarkTheme, themeToCss | | Interaction | resolveKey (the key map), navigateGrid / navigateTimeline, tabStopIndex, KeyboardEditSession, the pointer gesture machine (startGesture, DRAG_THRESHOLD_PX, LONG_PRESS_MS), autoScrollDelta, createAnnouncer, taskAccessibleName | | State models | buildToolbar, resolveChartState / skeletonRows, buildLegend / legendPlacement, buildTooltipModel / reduceTooltip / placeTooltip, selection and saved state | | Tree data | flattenTree, filterVisible, reindexVisible, sortRoots, columnComparator, findRowById, collectDescendants, buildDefaultColumns | | Editing | GanttChange and the pipeline (taskChange / dragChange / progressChange / linkChange, applyChange, invertChange, prepareChange), GanttHistory, validateChange / editRules / cellEditable, resolveCellEditor / commitCellValue, parsePredecessors / parseDuration, ProgressSession / LinkSession, resolveEditing | | Export | createExportSource (a chart snapshot without a binding), exportChartSvg, exportChartCsv, exportChartPages (print pages), buildExportModel / renderExportSvg, paginateChart, planRaster, exportFileName / exportFileText, resolveExportCall, sanitizeSvgMarkup (the custom-bar markup rules) | | Scheduling | computeCriticalPath(tasks, resolveConfig(options)) (CPM with FS/SS/FF/SF dependencies and lag, in working time with a calendar), longestChain | | Working calendar | createWorkingCalendar (WorkingCalendar: addWorking, snapStart / snapEnd, workingDuration…), formatDuration / formatFloat, taskDuration / spanDuration / measureBetween / addDuration, snapTaskStart / snapTaskEnd / followTaskEnd, editCalendar, dateReadingOf / sameDateReading, DEFAULT_WORKING_HOURS | | Resources | GanttResource / GanttTask.resources, indexResources, parseAssignments / formatAssignments, computeResourceUtilization (the daily load, loadAt, contributorsAt), projectResourceRows / resourceViewTasks (the synthetic rows of rows: 'resources'), computeLoadVisuals / hitTestLoad, buildResourceTooltip, resourceInfoOf, toggleRowsMode, LOAD_STYLE | | i18n | DEFAULT_LABELS, DEFAULT_FORMATS |

Every Gantry binding paints these models, which is why an option behaves the same everywhere; the options themselves are documented in the main README's Configuration.

import { computeCriticalPath, DependencyType } from '@gantryjs/core';

const { criticalIds } = computeCriticalPath([
  { id: 'a', name: 'Design', start: new Date('2026-01-05'), end: new Date('2026-01-20') },
  {
    id: 'b',
    name: 'Build',
    start: new Date('2026-01-21'),
    end: new Date('2026-02-28'),
    dependency: { taskId: 'a', type: DependencyType.FS },
  },
]);

Exports run here too, with no DOM: the same chart gives the same SVG and CSV as the bindings' exportSvg() / exportCsv(), so you can render a plan on a server or in a worker (Export and print):

import { createExportSource, exportChartCsv, exportChartPages, exportChartSvg, exportFileText } from '@gantryjs/core';

const source = createExportSource({ tasks, options: { viewMode: 'Week' }, now: new Date(2026, 0, 15) });
const svg = exportFileText('svg', exportChartSvg(source, { theme: 'light' })); // an .svg file's text
const csv = exportChartCsv(source, { columns: 'all', delimiter: ';' }); // RFC 4180, formulas neutralised
const { pages } = exportChartPages(source, { paper: 'a4' }); // one SVG per printed page

@gantryjs/core is published one file per module, so a bundler leaves out what an app never imports (the export code, for instance, until a chart exports).

Sample data for demos and docs lives in a separate entry point, @gantryjs/core/demo:

import { createDemoData, anchorToToday, DEMO_TASKS } from '@gantryjs/core/demo';

const { tasks, annotations } = createDemoData(); // today ≈ 40% into the plan
const later = createDemoData({ now: new Date(2027, 0, 4), at: 0.8 });
const mine = anchorToToday(myTemplate, { at: 0.5 }).tasks; // any template, whole-week shift

DEMO_TASKS / DEMO_ANNOTATIONS are the fixed 2026 reference plan.

License

MIT