InfiniteLoader component inspired by react-virtualized but for use with react-window
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# Yarn
yarn add react-window-infinite-loader
# NPM
npm install --save react-window-infinite-loader| Name | Type | Description |
|---|---|---|
children |
({ onItemsRendered: Function, ref: React$Ref }) => React$Node |
Render prop. See below for example usage. |
isItemLoaded |
(index: number) => boolean |
Function responsible for tracking the loaded state of each item. |
itemCount |
number |
Number of rows in list; can be arbitrary high number if actual number is unknown. |
loadMoreItems |
(startIndex: number, stopIndex: number) => Promise<void> |
Callback to be invoked when more rows must be loaded. It should return a Promise that is resolved once all data has finished loading. |
minimumBatchSize |
?number |
Minimum number of rows to be loaded at a time; defaults to 10. This property can be used to batch requests to reduce HTTP requests. |
threshold |
?number |
Threshold at which to pre-fetch data; defaults to 15. A threshold of 15 means that data will start loading when a user scrolls within 15 rows. |
The snippet below shows a basic example of how the InfiniteLoader can be used to wrap either a FixedSizeList or VariableSizeList from react-window.
// This value is arbitrary.
// If you know the size of your remote data, you can provide a real value.
// You can also increase this value gradually (as shown in the example below).
const itemCount = 1000;
<InfiniteLoader
isItemLoaded={isItemLoaded}
itemCount={itemCount}
loadMoreItems={loadMoreItems}
>
{({ onItemsRendered, ref }) => (
<FixedSizeList
itemCount={itemCount}
onItemsRendered={onItemsRendered}
ref={ref}
{...otherListProps}
/>
)}
</InfiniteLoader>The InfiniteLoader component was created to help break large data sets down into chunks that could be just-in-time loaded as they were scrolled into view.
It can also be used to create infinite loading lists (e.g. Facebook or Twitter).
Here's a basic example of how you might implement that:
function ExampleWrapper({
// Are there more items to load?
// (This information comes from the most recent API request.)
hasNextPage,
// Are we currently loading a page of items?
// (This may be an in-flight flag in your Redux store for example.)
isNextPageLoading,
// Array of items loaded so far.
items,
// Callback function responsible for loading the next page of items.
loadNextPage
}) {
// If there are more items to be loaded then add an extra row to hold a loading indicator.
const itemCount = hasNextPage ? items.length 1 : items.length;
// Only load 1 page of items at a time.
// Pass an empty callback to InfiniteLoader in case it asks us to load more than once.
const loadMoreItems = isNextPageLoading ? () => {} : loadNextPage;
// Every row is loaded except for our loading indicator row.
const isItemLoaded = index => !hasNextPage || index < items.length;
// Render an item or a loading indicator.
const Item = ({ index, style }) => {
let content;
if (!isItemLoaded(index)) {
content = "Loading...";
} else {
content = items[index].name;
}
return <div style={style}>{content}</div>;
};
return (
<InfiniteLoader
isItemLoaded={isItemLoaded}
itemCount={itemCount}
loadMoreItems={loadMoreItems}
>
{({ onItemsRendered, ref }) => (
<FixedSizeList
itemCount={itemCount}
onItemsRendered={onItemsRendered}
ref={ref}
{...props}
>
{Item}
</FixedSizeList>
)}
</InfiniteLoader>
);
}Some use cases require cached items to be reset. For example, after a list has been sorted, previously cached items may be invalid. You can let InfiniteLoader know that it needs to reload cached items by calling the resetloadMoreItemsCache method.
function ExampleWrapper({
// ...
sortOrder,
}) {
// We create a reference for the InfiniteLoader
const infiniteLoaderRef = useRef(null);
const hasMountedRef = useRef(false);
// Each time the sort prop changed we called the method resetloadMoreItemsCache to clear the cache
useEffect(() => {
// We only need to reset cached items when "sortOrder" changes.
// This effect will run on mount too; there's no need to reset in that case.
if (hasMountedRef.current) {
if (infiniteLoaderRef.current) {
infiniteLoaderRef.current.resetloadMoreItemsCache();
}
}
hasMountedRef.current = true;
}, [sortOrder]);
// ...
// We passed down the ref to the InfiniteLoader component
return (
<InfiniteLoader
ref={infiniteLoaderRef}
isItemLoaded={isItemLoaded}
itemCount={itemCount}
loadMoreItems={loadMoreItems}
>
{({ onItemsRendered, ref }) => (
// ...
)}
</InfiniteLoader>
);
}MIT © bvaughn