Support loading more results in Vector search client

This lets users scroll to load additional search results. To match the
old search more closely, we’ll also want to reduce the number of results
initially shown (should be fewer than the number of loaded results), but
that can be done separately.

Bug: T322333
Change-Id: I67fac3b209d6a1ab2661e1e1c0681edd8472ac6c
Depends-On: Iadade9cbf48457cfeabc78439624602ec3f98782

repo/resources/wikibase.vector.searchClient.js

@@ -55,6 +55,9 @@
 	const vectorSearchClient = {
 		fetchByTitle: ( q, limit = 10, _showDescription = true ) => {
 			return fetchResults( q, limit );
+		},
+		loadMore: ( q, offset, limit = 10, _showDescription = true ) => {
+			return fetchResults( q, limit, offset );
 		}
 	};
 

repo/tests/jest/wikibase.vector.searchClient.spec.js

@@ -42,7 +42,15 @@ describe( 'Vector Search Client', () => {
 		]
 	} ];
 
-	it( 'test construction and fetchByTitle behavior', async () => {
+	beforeEach( () => {
+		// ensure that require( searchClient.js ) has the side-effect we want to test each time
+		jest.resetModules();
+	} );
+
+	it.each( [
+		[ 'fetchByTitle' ],
+		[ 'loadMore' ]
+	] )( 'test construction and %s behavior', async ( name ) => {
 		const fakeApiInstance = {
 			get: jest.fn().mockResolvedValue( {
 				search: mockApiResults
@@ -62,14 +70,10 @@ describe( 'Vector Search Client', () => {
 		const vectorSearchClient = global.mw.config.set.mock.calls[ 0 ][ 1 ];
 
 		const exampleSearchString = 'abc';
+		const vectorOffset = 20;
 		const vectorLimit = 10;
 
-		const apiController = vectorSearchClient.fetchByTitle(
-			exampleSearchString,
-			vectorLimit,
-			true
-		);
-		expect( fakeApiInstance.get ).toHaveBeenCalledWith( {
+		const expectedParams = {
 			action: 'wbsearchentities',
 			search: exampleSearchString,
 			limit: vectorLimit,
@@ -78,7 +82,26 @@ describe( 'Vector Search Client', () => {
 			type: 'item',
 			format: 'json',
 			errorformat: 'plaintext'
-		} );
+		};
+		let apiController;
+		if ( name === 'fetchByTitle' ) {
+			apiController = vectorSearchClient.fetchByTitle(
+				exampleSearchString,
+				vectorLimit,
+				true
+			);
+		} else if ( name === 'loadMore' ) {
+			apiController = vectorSearchClient.loadMore(
+				exampleSearchString,
+				vectorOffset,
+				vectorLimit,
+				true
+			);
+			expectedParams.continue = vectorOffset;
+		} else {
+			throw new Error( `Unexpected test name ${name}` );
+		}
+		expect( fakeApiInstance.get ).toHaveBeenCalledWith( expectedParams );
 
 		const actualTransformedResult = await apiController.fetch;
 		expect( actualTransformedResult ).toStrictEqual( {