Documentation / @finchart/core / index / isGap

Function: isGap()

isGap(value): value is null | undefined

Defined in: packages/core/src/data/accessors.ts:23

Is this value a gap — a spot with nothing to draw?

null being a gap is a contract the README teaches with its warmup example. undefined counts too: a close missing from one exchange row that arrives as undefined, and a consumer who deliberately wrote null, mean the same thing on screen.

getY doesn't fold this to ?? null because assertReadableValue needs getY(point) === undefined to point a consumer with a wrong field name toward the fix — if the accessor swallowed undefined, that guidance would never fire, and the consumer would just see a blank chart with no explanation.

Parameters

value

number | null | undefined

Returns

value is null | undefined