vikunja-frontend/src/helpers/calculateItemPosition.ts
konrad 3c7f8d7aa2 Reorder tasks, lists and kanban buckets (#620)
Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/620
Co-authored-by: konrad <konrad@kola-entertainments.de>
Co-committed-by: konrad <konrad@kola-entertainments.de>
2021-07-28 19:56:29 +00:00

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TypeScript

export const calculateItemPosition = (positionBefore: number | null, positionAfter: number | null): number => {
if (positionBefore === null && positionAfter === null) {
return 0
}
// If there is no task before, our task is the first task in which case we let it have half of the position of the task after it
if (positionBefore === null && positionAfter !== null) {
return positionAfter / 2
}
// If there is no task after it, we just add 2^16 to the last position to have enough room in the future
if (positionBefore !== null && positionAfter === null) {
return positionBefore + Math.pow(2, 16)
}
// If we have both a task before and after it, we acually calculate the position
// @ts-ignore - can never be null but TS does not seem to understand that
return positionBefore + (positionAfter - positionBefore) / 2
}