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chore: (scroller) combine scroll directions to single function

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This commit is contained in:
Grady Hallenbeck 2023-10-16 20:38:25 -07:00
parent c223b7c2d7
commit 76e3761ffd
1 changed files with 51 additions and 49 deletions
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100
src/utils/scroller.ts
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@ -7,29 +7,39 @@ export enum ScrollDirection {
} }
interface ScrollState { interface ScrollState {
scrollPosition: number; scrollPos: number;
} }
interface ScrollerSlideViewWindowProps {
interface ScrollerItemSlideIntoViewProps {
direction: ScrollDirection; direction: ScrollDirection;
scroller: ScrollerFactory | null; scroller: ScrollerFactory | null;
scrollState: ScrollState; scrollState: ScrollState;
} }
export function scrollerItemSlideIntoView({ direction, scroller, scrollState }: ScrollerSlideViewWindowProps) {
interface ScrollToWindowProps {
scroller: ScrollerFactory;
items: HTMLElement[];
scrollState: ScrollState;
direction: ScrollDirection
}
export function scrollerItemSlideIntoView({ direction, scroller, scrollState }: ScrollerItemSlideIntoViewProps) {
if (!scroller) { if (!scroller) {
return; return;
} }
const slider: HTMLElement = scroller.getScrollSlider(); const slider: HTMLElement = scroller.getScrollSlider();
const items = [...slider.children]; const items = [...slider.children] as HTMLElement[];
if (direction === ScrollDirection.LEFT) { scrollToWindow({
scrollToPreviousVisibleWindow(scroller, items as HTMLElement[], scrollState); scroller,
} else { items,
scrollToNextVisibleWindow(scroller, items as HTMLElement[], scrollState); scrollState,
} direction
});
} }
function getFirstAndLastVisible(scrollFrame: HTMLElement, items: HTMLElement[], { scrollPosition }: ScrollState) { function getFirstAndLastVisible(scrollFrame: HTMLElement, items: HTMLElement[], { scrollPos: scrollPosition }: ScrollState) {
const isRTL = globalize.getIsRTL(); const isRTL = globalize.getIsRTL();
const localeModifier = isRTL ? -1 : 1; const localeModifier = isRTL ? -1 : 1;
@ -46,56 +56,48 @@ function getFirstAndLastVisible(scrollFrame: HTMLElement, items: HTMLElement[],
return [firstVisibleIndex, lastVisibleIndex]; return [firstVisibleIndex, lastVisibleIndex];
} }
function scrollToNextVisibleWindow(scroller: ScrollerFactory, items: HTMLElement[], scrollState: ScrollState) { function scrollToWindow({
const isRTL = globalize.getIsRTL(); scroller,
items,
scrollState,
direction = ScrollDirection.RIGHT
}: ScrollToWindowProps) {
// When we're rendering RTL, scrolling toward the end of the container is toward the left so all of our scroll // When we're rendering RTL, scrolling toward the end of the container is toward the left so all of our scroll
// positions need to be negative. // positions need to be negative.
const localeModifier = isRTL ? -1 : 1;
// NOTE: Legacy scroller passing in an Element which is the frame element and has some of the scroller factory
// functions on it, but is not a true scroller factory. For legacy, we need to pass `scroller` directly instead
// of getting the frame from the factory instance.
const [, lastVisibleIndex] = getFirstAndLastVisible(scroller.getScrollFrame?.() || scroller, items, scrollState);
const nextItem = items[lastVisibleIndex];
const nextItemScrollOffset = lastVisibleIndex * nextItem.offsetWidth;
// This will be the position to anchor the item at `lastVisibleIndex` to the start of the view window.
const nextItemScrollPos = (nextItemScrollOffset) * localeModifier;
if (scroller.slideTo) {
scroller.slideTo(nextItemScrollPos, false, undefined);
} else {
// @ts-expect-error Legacy support passes in a `scroller` that isn't a ScrollFactory
scroller.scrollToPosition(nextItemScrollPos);
}
}
function scrollToPreviousVisibleWindow(scroller: ScrollerFactory, items: HTMLElement[], scrollState: ScrollState) {
// NOTE: Legacy scroller passing in an Element which is the frame element and has some of the scroller factory
// functions on it, but is not a true scroller factory. For legacy, we need to pass `scroller` directly instead
// of getting the frame from the factory instance.
const frame = scroller.getScrollFrame?.() || scroller;
const isRTL = globalize.getIsRTL(); const isRTL = globalize.getIsRTL();
// When we're rendering RTL, scrolling toward the end of the container is toward the left so all of our scroll
// positions need to be negative.
const localeModifier = isRTL ? -1 : 1; const localeModifier = isRTL ? -1 : 1;
const [firstVisibleIndex] = getFirstAndLastVisible(frame, items, scrollState); // NOTE: The legacy scroller is passing in an Element which is the frame element and has some of the scroller
// factory functions on it, but is not a true scroller factory. For legacy, we need to pass `scroller` directly
// instead of getting the frame from the factory instance.
const frame = scroller.getScrollFrame?.() ?? scroller;
const [firstVisibleIndex, lastVisibleIndex] = getFirstAndLastVisible(frame, items, scrollState);
const previousItem = items[firstVisibleIndex]; let scrollToPosition: number;
const previousItemScrollOffset = firstVisibleIndex * previousItem.offsetWidth;
// Find the total number of items that can fit in a view window and subtract one to account for item at if (direction === ScrollDirection.RIGHT) {
// `firstVisibleIndex`. The total width of these items is the amount that we need to adjust the scroll position by const nextItem = items[lastVisibleIndex];
// to anchor item at `firstVisibleIndex` to the end of the view window.
const offsetAdjustment = (Math.floor(frame.offsetWidth / previousItem.offsetWidth) - 1) * previousItem.offsetWidth;
const previousItemScrollPos = (previousItemScrollOffset - offsetAdjustment) * localeModifier; // This will be the position to anchor the item at `lastVisibleIndex` to the start of the view window.
const nextItemScrollOffset = lastVisibleIndex * nextItem.offsetWidth;
scrollToPosition = nextItemScrollOffset * localeModifier;
} else {
const previousItem = items[firstVisibleIndex];
const previousItemScrollOffset = firstVisibleIndex * previousItem.offsetWidth;
// Find the total number of items that can fit in a view window and subtract one to account for item at
// `firstVisibleIndex`. The total width of these items is the amount that we need to adjust the scroll position by
// to anchor item at `firstVisibleIndex` to the end of the view window.
const offsetAdjustment = (Math.floor(frame.offsetWidth / previousItem.offsetWidth) - 1) * previousItem.offsetWidth;
// This will be the position to anchor the item at `firstVisibleIndex` to the end of the view window.
scrollToPosition = (previousItemScrollOffset - offsetAdjustment) * localeModifier;
}
if (scroller.slideTo) { if (scroller.slideTo) {
scroller.slideTo(previousItemScrollPos, false, undefined); scroller.slideTo(scrollToPosition, false, undefined);
} else { } else {
// @ts-expect-error Legacy support passes in a `scroller` that isn't a ScrollFactory // @ts-expect-error Legacy support passes in a `scroller` that isn't a ScrollFactory
scroller.scrollToPosition(previousItemScrollPos); scroller.scrollToPosition(scrollToPosition);
} }
} }