data-paging-manager

data-paging-manager is a Typescript-first React library to paginate data, cache it and display it in different forms.

Install

npm install --save data-paging-manager

Usage

To use the library, you need to define a data source, which is achieved extending the PagingSource class. After that, you can choose between PagingContainer and ListPagingContainer to display the data

PagingSource

PagingSource is an abstract class with which you define how the React components get the data. It is a generic class where T is the type of a single element from the dataset that the user wants to display There are two methods that need to be overridden:

protected async abstract _getPage(pageIndex:number):Promise<T[]>

If we think of portion of fixed length of data as a page, this method defines how does the library fetch the page at index pageIndex . Internally, this method is used to fetch and cache the data in pages. The method returns a promise that holds a page of data, meaning a list that holds a portion of the whole dataset.

public async abstract getDatasetSize():Promise<number>

This method returns the size of the entire dataset that gets paginates.

The constructor of PagingSource gets a single parameter, pageSize : number which means how many items are per page.

PagingsSource cahces all pages that get requested and also when a page gets requested it also asynchronously pre-fetches and caches adjacent pages for a smoother experience. When requesting a page, it becomes available to be consumed before the pre-fetching starts.

PagingSource - properties and methods available

• PageIndex : number - The index of the page that is currently shown to the user
• CurrentPage : Promise<T> - A property that holds the current page
• async changePage(pageIndex:number : Promise<void> - Function that changes the current page. The function returs when the page gets availabele. It doesn't return the actuall page. For that you need to access CurrentPage after this function returns
• pageSize: number -The number of items are per page

PagingContainer<T>

This is the main component to display the data that is being paged. It gets a PagingSource as a prop and passes down a set of PagingProps to its children. It is a generic where T is the type of a single item from the dataset.

PagingContainer props

• pagingSource : PagingSource\<T>
• style : React.CSSProperties? - styles to be passed to the container
• className : string? - CSS class to be passed to the container

PagingProps<T>

• data: T[] - A page of data, where each item has a type of T
• next : () => void - Function to request the next page
• prev : () =>void - Function to request the previous page
• pageIndex : number - The index of the current page

ListPagingContainer<T>

The other component that can display the paged data. Unlike PagingContainer it gets a ReactElement as a prop and manages the list of items itself.

The UI isn't as customizable as a consequence, but it is easier to implement and it enables infinite scrolling ( pages get fetched automatically when a scroll threshold is met). It is also a generic.

For infinite scroll mode, PagingSource.pageSize refers to how many items gets fetched at once.

ListPagingContainer props

• pagingSource : PagingSource\<T>
• style : React.CSSProperties? - styles to be passed to the container
• className : string? - CSS class to be passed to the container
• element : (data : T) => ReactElement - A function that gets a single item from the current page and returns a ReactElement to display that item
• pageIndex : number? - The index of the page to be displayed. Unlike PagingContainer this isn't handled internally. It is not required when infiniteScroll is true
• infiniteScroll : boolean? - A flag to set the infinite scroll mode. Defaults to false
• threshold : number? - When the item with this index (counting from the bottom) is visible, fetch the next page. Only used for infinite scroll mode. Defaults to 1