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Documentation / @finchart/core / index / InfiniteHistoryCursorOptions

Interface: InfiniteHistoryCursorOptions<T, C> ​

Defined in: packages/core/src/extensions/infinite-history.ts:161

The cursor mode's options. from is still the first x held — trimming and gap judgment stay in the chart's x — and cursor is the token for the page before it, the next that came with the page already held.

Extends ​

Type Parameters ​

T ​

T extends BaseDataPoint

C ​

C

Properties ​

coordinates? ​

optional coordinates?: CoordinateAccessor<T>

Defined in: packages/core/src/extensions/infinite-history.ts:115

The accessor the sink's series uses, so a landed page is judged by the same rule the sink will apply — notably uniqueX (a bar per moment). Omitted, the loader checks order only, as line data allows. A page that fails here is a fetch shape defect (the loader terminates); without this, the same page would fail inside the sink and read as a delivery failure that retries on every gesture. The cursor — from, before, the trim, the next frontier — lives in the same space: the x the accessor reads (getX), which is the x the chart orders by. For every built-in accessor that is point.x. Omitted, the loader checks x order only — it does not know the point's shape, so it asks nothing of its values.

Inherited from ​

HistoryOptionsBase.coordinates

cursor ​

cursor: C

Defined in: packages/core/src/extensions/infinite-history.ts:163

from ​

from: number

Defined in: packages/core/src/extensions/infinite-history.ts:125

The cursor origin: the first x the consumer already holds. Required because every value the loader could guess is wrong for some registration — the plot's data range is a union across all series (a neighbor starting earlier would leave a permanent hole), and a handle's own range is the drawn side, which a derivation shortens by its warm-up. The consumer never invents this value: it just received its own first page.

Inherited from ​

HistoryOptionsBase.from

screensAhead? ​

optional screensAhead?: number

Defined in: packages/core/src/extensions/infinite-history.ts:134

Prefetch when the loaded past to the left of the view is thinner than this many screen widths. Default 1 — the repo's two hand-rolled loaders used 0.3–0.5 against synchronous generators, and with a network round-trip in the way one full screen of runway is what keeps blank space from flashing in during a scroll. Lower it to trade that for fewer requests.

Inherited from ​

HistoryOptionsBase.screensAhead

viewFrontier? ​

optional viewFrontier?: () => { plottedX: number; sourceX: number; } | null

Defined in: packages/core/src/extensions/infinite-history.ts:143

Bridge a source whose x differs from the x drawn on the chart (for example, time-stamped candles rendered as ordinal Renko bricks). sourceX is the first source point the sink has committed; plottedX is the first drawn point. Both must be read from the same committed state. Return null while the derivation has no drawn points yet. The fetch cursor still uses from and the page's source x.

Returns ​

{ plottedX: number; sourceX: number; } | null

Inherited from ​

HistoryOptionsBase.viewFrontier