19 lines
624 B
TypeScript
19 lines
624 B
TypeScript
|
/**
|
||
|
|
* Maps a horizontal swipe delta to a cycle direction. A leftward swipe (negative
|
||
|
|
* dx) advances to the next pairing (+1); a rightward swipe (positive dx) goes to
|
||
|
|
* the previous (-1). Movement below the threshold is ignored (0).
|
||
|
|
*
|
||
|
|
* @param dx - Horizontal travel in px (end minus start).
|
||
|
|
* @param threshold - Minimum absolute travel in px to count as a swipe.
|
||
|
|
* @returns +1 (next), -1 (previous), or 0 (no cycle).
|
||
|
|
*/
|
||
|
|
export function swipeDirection(dx: number, threshold: number): -1 | 0 | 1 {
|
||
|
|
if (dx <= -threshold) {
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
if (dx >= threshold) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
return 0;
|
||
|
|
}
|