From dbfafe25e3230d5efa0406ea7a297af4633ed800 Mon Sep 17 00:00:00 2001 From: dakkar Date: Fri, 19 Apr 2024 13:35:18 +0100 Subject: [PATCH] rework pagination - fixes #491 previously, when adding items either at the beginnig (e.g. new notes coming in while we're not looking at the top of the timeline) or a the end (e.g. more items arriving from a background fetch) of a paginated view, the resulting list got truncated to `displayLimit`, potentially throwing data away and causing a new fetch. This, coupled with the async nature of scrolling & fetching, could cause weird results. Also, `offset` was always incremented by the size of the fetched results, even if not all of them were displayed, meant that it was possible for offset-based pagination to drop items. Finally, the "queue" of new items (usually, new notes) also got truncated to `displayLimit`, which again could drop items (this effect was usually masked by the first point: when scrolling to the top of the timeline, if the queue's length was equal to `displayLimit`, those notes displaced any existing ones, `unshiftItems` set `more.value=true`, you got scrolled to the top, and notes were fetched again, so you lost your position but at least all notes got shown, eventually) --- .../frontend/src/components/MkPagination.vue | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/packages/frontend/src/components/MkPagination.vue b/packages/frontend/src/components/MkPagination.vue index 62a85389a..6f6007d43 100644 --- a/packages/frontend/src/components/MkPagination.vue +++ b/packages/frontend/src/components/MkPagination.vue @@ -395,10 +395,10 @@ const prepend = (item: MisskeyEntity): void => { * @param newItems 新しいアイテムの配列 */ function unshiftItems(newItems: MisskeyEntity[]) { - const length = newItems.length + items.value.size; - items.value = new Map([...arrayToEntries(newItems), ...items.value].slice(0, props.displayLimit)); - - if (length >= props.displayLimit) more.value = true; + const prevLength = items.value.size; + items.value = new Map([...arrayToEntries(newItems), ...items.value].slice(0, newItems.length + props.displayLimit)); + // if we truncated, mark that there are more values to fetch + if (items.value.size < prevLength) more.value = true; } /** @@ -406,10 +406,10 @@ function unshiftItems(newItems: MisskeyEntity[]) { * @param oldItems 古いアイテムの配列 */ function concatItems(oldItems: MisskeyEntity[]) { - const length = oldItems.length + items.value.size; - items.value = new Map([...items.value, ...arrayToEntries(oldItems)].slice(0, props.displayLimit)); - - if (length >= props.displayLimit) more.value = true; + const prevLength = items.value.size; + items.value = new Map([...items.value, ...arrayToEntries(oldItems)].slice(0, oldItems.length + props.displayLimit)); + // if we truncated, mark that there are more values to fetch + if (items.value.size < prevLength) more.value = true; } function executeQueue() { @@ -418,7 +418,7 @@ function executeQueue() { } function prependQueue(newItem: MisskeyEntity) { - queue.value = new Map([[newItem.id, newItem], ...queue.value].slice(0, props.displayLimit) as [string, MisskeyEntity][]); + queue.value = new Map([[newItem.id, newItem], ...queue.value] as [string, MisskeyEntity][]); } /*