@roadline/core

The engine behind Roadline, a headless timeline / Gantt library. Plain TypeScript: no React, no DOM, no dependencies.

Most people want @roadline/react. Install this directly to drive a timeline from another framework, or to use the pieces on their own.

npm install @roadline/core

Scale — toPx, toTime, zoomAt, panBy, fitRange, clampScale, visibleRange. A scale is { start, msPerPx }; zooming is anchored, so the instant under the cursor stays under the cursor even at the zoom limits.

Ticks — chooseTier, generateTicks, alignTick, formatTick. Generation is a calendar walk rather than a fixed millisecond step, so months keep their real lengths and DST days their real durations.

Dates — createDateAdapter({ timeZone, locale, weekStartsOn }). Any IANA zone with nothing to ship: offsets are resolved through Intl.DateTimeFormat.formatToParts. Wall-clock times that do not exist or occur twice — the two DST edges — are resolved explicitly rather than by rounding.

Data — createItemIndex (bucketed interval index; a viewport query over 50 000 items takes about 0.13 ms), buildGroupTree, groupSummaries, computeRowWindow.

Interactions — reduceInteraction, a pure gesture state machine with no DOM, plus snapTime and edgeScrollVelocity.

Links — elbowPath and friends: orthogonal routing for dependency arrows, FS / SS / FF / SF.

import { fitRange, toPx, zoomAt } from '@roadline/core'

let scale = fitRange({ start: q1Start, end: q1End }, 800)
scale = zoomAt(scale, 400, 2)        // zoom in around the middle
const x = toPx(scale, Date.now())

MIT