Newswires UI: add pagination

newswires/client/src/WireItemTable.tsx

@@ -1,4 +1,5 @@
 import {
+	EuiButton,
 	EuiFlexGroup,
 	euiScreenReaderOnly,
 	EuiTable,
@@ -13,6 +14,7 @@ import {
 	useEuiTheme,
 } from '@elastic/eui';
 import { css } from '@emotion/react';
+import { useState } from 'react';
 import sanitizeHtml from 'sanitize-html';
 import { useSearch } from './context/SearchContext.tsx';
 import { formatTimestamp } from './formatTimestamp';
@@ -31,38 +33,63 @@ const fadeOutBackground = css`
 `;
 
 export const WireItemTable = ({ wires }: { wires: WireData[] }) => {
-	const { config, handleSelectItem } = useSearch();
+	const { config, handleSelectItem, loadMoreResults } = useSearch();
+
+	const [isLoadingMore, setIsLoadingMore] = useState<boolean>(false);
 
 	const selectedWireId = config.itemId;
 
+	const handleLoadMoreResults = () => {
+		if (wires.length > 0) {
+			setIsLoadingMore(true);
+
+			const beforeId = Math.min(...wires.map((wire) => wire.id)).toString();
+
+			void loadMoreResults(beforeId).finally(() => {
+				setIsLoadingMore(false);
+			});
+		}
+	};
+
 	return (
-		<EuiTable
-			tableLayout="auto"
-			responsiveBreakpoint={config.view === 'item' ? true : 'm'}
-		>
-			<EuiTableHeader
+		<>
+			<EuiTable
+				tableLayout="auto"
+				responsiveBreakpoint={config.view === 'item' ? true : 'm'}
+			>
+				<EuiTableHeader
+					css={css`
+						${euiScreenReaderOnly()}
+					`}
+				>
+					<EuiTableHeaderCell>Headline</EuiTableHeaderCell>
+					<EuiTableHeaderCell>Version Created</EuiTableHeaderCell>
+				</EuiTableHeader>
+				<EuiTableBody>
+					{wires.map(({ id, supplier, content, isFromRefresh, highlight }) => (
+						<WireDataRow
+							key={id}
+							id={id}
+							supplier={supplier}
+							content={content}
+							isFromRefresh={isFromRefresh}
+							highlight={highlight}
+							selected={selectedWireId == id.toString()}
+							handleSelect={handleSelectItem}
+						/>
+					))}
+				</EuiTableBody>
+			</EuiTable>
+			<EuiButton
+				isLoading={isLoadingMore}
 				css={css`
-					${euiScreenReaderOnly()}
+					margin-top: 12px;
 				`}
+				onClick={handleLoadMoreResults}
 			>
-				<EuiTableHeaderCell>Headline</EuiTableHeaderCell>
-				<EuiTableHeaderCell>Version Created</EuiTableHeaderCell>
-			</EuiTableHeader>
-			<EuiTableBody>
-				{wires.map(({ id, supplier, content, isFromRefresh, highlight }) => (
-					<WireDataRow
-						key={id}
-						id={id}
-						supplier={supplier}
-						content={content}
-						isFromRefresh={isFromRefresh}
-						highlight={highlight}
-						selected={selectedWireId == id.toString()}
-						handleSelect={handleSelectItem}
-					/>
-				))}
-			</EuiTableBody>
-		</EuiTable>
+				{isLoadingMore ? 'Loading' : 'Load more'}
+			</EuiButton>
+		</>
 	);
 };
 
@@ -101,6 +128,7 @@ const WireDataRow = ({
 					background-color: ${primaryBgColor};
 					border-left: 4px solid ${theme.euiTheme.colors.accent};
 				}
+
 				border-left: 4px solid
 					${selected ? theme.euiTheme.colors.primary : 'transparent'};
 				${isFromRefresh ? fadeOutBackground : ''}

newswires/client/src/context/SearchContext.tsx

@@ -77,6 +77,10 @@ const ActionSchema = z.discriminatedUnion('type', [
 		query: QuerySchema,
 		data: WiresQueryResponseSchema,
 	}),
+	z.object({
+		type: z.literal('APPEND_RESULTS'),
+		data: WiresQueryResponseSchema,
+	}),
 	z.object({ type: z.literal('FETCH_ERROR'), error: z.string() }),
 	z.object({ type: z.literal('RETRY') }),
 	z.object({ type: z.literal('SELECT_ITEM'), item: z.string().optional() }),
@@ -100,6 +104,7 @@ export type SearchContextShape = {
 	handleNextItem: () => void;
 	handlePreviousItem: () => void;
 	toggleAutoUpdate: () => void;
+	loadMoreResults: (beforeId: string) => Promise<void>;
 };
 export const SearchContext: Context<SearchContextShape | null> =
 	createContext<SearchContextShape | null>(null);
@@ -176,7 +181,7 @@ export function SearchContextProvider({ children }: PropsWithChildren) {
 									...state.queryData.results.map((wire) => wire.id),
 								).toString()
 							: undefined;
-					fetchResults(currentConfig.query, sinceId)
+					fetchResults(currentConfig.query, { sinceId })
 						.then((data) => {
 							dispatch({ type: 'UPDATE_RESULTS', data });
 						})
@@ -274,6 +279,18 @@ export function SearchContextProvider({ children }: PropsWithChildren) {
 		dispatch({ type: 'TOGGLE_AUTO_UPDATE' });
 	};
 
+	const loadMoreResults = async (beforeId: string): Promise<void> => {
+		return fetchResults(currentConfig.query, { beforeId })
+			.then((data) => {
+				dispatch({ type: 'APPEND_RESULTS', data });
+			})
+			.catch((error) => {
+				const errorMessage =
+					error instanceof Error ? error.message : 'unknown error';
+				dispatch({ type: 'FETCH_ERROR', error: errorMessage });
+			});
+	};
+
 	return (
 		<SearchContext.Provider
 			value={{
@@ -286,6 +303,7 @@ export function SearchContextProvider({ children }: PropsWithChildren) {
 				handleNextItem,
 				handlePreviousItem,
 				toggleAutoUpdate,
+				loadMoreResults,
 			}}
 		>
 			{children}

newswires/client/src/context/SearchReducer.test.ts

@@ -98,6 +98,31 @@ describe('SearchReducer', () => {
 		});
 	});
 
+	it(`should handle APPEND_RESULTS action in success state`, () => {
+		const state: State = {
+			...successState,
+			queryData: { results: [{ ...sampleWireData, id: 2 }] },
+		};
+
+		const action: Action = {
+			type: 'APPEND_RESULTS',
+			data: { results: [{ ...sampleWireData, id: 1 }] },
+		};
+
+		const newState = SearchReducer(state, action);
+
+		expect(newState.status).toBe('success');
+		expect(newState.queryData?.results).toHaveLength(2);
+		expect(newState.queryData?.results).toContainEqual({
+			...sampleWireData,
+			id: 1,
+		});
+		expect(newState.queryData?.results).toContainEqual({
+			...sampleWireData,
+			id: 2,
+		});
+	});
+
 	[
 		{ state: initialState, expectedStatus: 'error' },
 		{ state: successState, expectedStatus: 'offline' },

newswires/client/src/context/SearchReducer.ts

@@ -29,6 +29,20 @@ function mergeQueryData(
 	}
 }
 
+function appendQueryData(
+	existing: WiresQueryResponse | undefined,
+	newData: WiresQueryResponse,
+): WiresQueryResponse {
+	if (existing) {
+		return {
+			...newData,
+			results: [...existing.results, ...newData.results],
+		};
+	} else {
+		return newData;
+	}
+}
+
 function getUpdatedHistory(
 	previousHistory: SearchHistory,
 	newQuery: Query,
@@ -85,6 +99,12 @@ export const SearchReducer = (state: State, action: Action): State => {
 				default:
 					return state;
 			}
+		case 'APPEND_RESULTS':
+			return {
+				...state,
+				status: 'success',
+				queryData: appendQueryData(state.queryData, action.data),
+			};
 		case 'FETCH_ERROR':
 			switch (state.status) {
 				case 'loading':

newswires/client/src/context/fetchResults.test.ts

@@ -24,7 +24,7 @@ describe('fetchResults', () => {
 		const mockQuery = { q: 'value' };
 		await fetchResults(mockQuery);
 
-		expect(paramsToQuerystring).toHaveBeenCalledWith(mockQuery);
+		expect(paramsToQuerystring).toHaveBeenCalledWith(mockQuery, {});
 		expect(pandaFetch).toHaveBeenCalledWith('/api/search?queryString', {
 			headers: { Accept: 'application/json' },
 		});
@@ -70,11 +70,25 @@ describe('fetchResults', () => {
 
 	it('should append sinceId to the query if provided', async () => {
 		const mockQuery = { q: 'value' };
-		await fetchResults(mockQuery, '123');
+		await fetchResults(mockQuery, { sinceId: '123' });
 
-		expect(paramsToQuerystring).toHaveBeenCalledWith({
-			...mockQuery,
-			sinceId: '123',
-		});
+		expect(paramsToQuerystring).toHaveBeenCalledWith(
+			{
+				...mockQuery,
+			},
+			{ sinceId: '123' },
+		);
+	});
+
+	it('should append beforeId to the query if provided', async () => {
+		const mockQuery = { q: 'value' };
+		await fetchResults(mockQuery, { beforeId: '123' });
+
+		expect(paramsToQuerystring).toHaveBeenCalledWith(
+			{
+				...mockQuery,
+			},
+			{ beforeId: '123' },
+		);
 	});
 });

newswires/client/src/context/fetchResults.ts

@@ -5,12 +5,12 @@ import { paramsToQuerystring } from '../urlState.ts';
 
 export const fetchResults = async (
 	query: Query,
-	sinceId: string | undefined = undefined,
+	additionalParams: {
+		sinceId?: string;
+		beforeId?: string;
+	} = {},
 ): Promise<WiresQueryResponse> => {
-	const queryToSerialise = sinceId
-		? { ...query, sinceId: sinceId.toString() }
-		: query;
-	const queryString = paramsToQuerystring(queryToSerialise);
+	const queryString = paramsToQuerystring(query, additionalParams);
 	const response = await pandaFetch(`/api/search${queryString}`, {
 		headers: {
 			Accept: 'application/json',

newswires/client/src/urlState.ts

@@ -70,7 +70,13 @@ export const configToUrl = (config: Config): string => {
 
 export const paramsToQuerystring = (
 	config: Query,
-	sinceId: number | undefined = undefined,
+	{
+		sinceId,
+		beforeId,
+	}: {
+		sinceId?: string;
+		beforeId?: string;
+	} = {},
 ): string => {
 	const params = Object.entries(config).reduce<Array<[string, string]>>(
 		(acc, [k, v]) => {
@@ -89,7 +95,10 @@ export const paramsToQuerystring = (
 		[],
 	);
 	if (sinceId !== undefined) {
-		params.push(['sinceId', sinceId.toString()]);
+		params.push(['sinceId', sinceId]);
+	}
+	if (beforeId !== undefined) {
+		params.push(['beforeId', beforeId]);
 	}
 	const querystring = new URLSearchParams(params).toString();
 	return querystring.length !== 0 ? `?${querystring}` : '';