editor / cyclicItem

Function: cyclicItem()

cyclicItem<T>(items, index, fallback): T

Defined in: geometry/cyclic-item.ts:15

Item of a cyclic list at any integer index: indices are taken modulo the list length (Q11).

Index −1 is the last item, index n the first one. The index is reduced with a non-negative modulo, ((i mod n) + n) mod n, not with the sign-keeping % of JavaScript alone (ADR-0025).

Type Parameters

T

T

type of the items: a vertex, or a value per vertex

Parameters

items

readonly T[]

vertices of a contour, or one value per vertex, in drawing order

index

number

position, wrapped around the list

fallback

T

value returned when the list is empty

Returns

T

the item at index mod n, or fallback for an empty list

Kind

geometry

See

DERIV-turning-angle