From d3f344fe6193d7cd86e03e7a00770032e7919ab4 Mon Sep 17 00:00:00 2001
From: Dave Smith <getdavemail@gmail.com>
Date: Mon, 2 Dec 2024 13:17:45 +0000
Subject: [PATCH] Prefer exact matches in Link Search results sorting (#67367)

* Weight towards exact matches

* Add additional test coverage

Co-authored-by: getdave <get_dave@git.wordpress.org>
Co-authored-by: draganescu <andraganescu@git.wordpress.org>
Co-authored-by: talldan <talldanwp@git.wordpress.org>
Co-authored-by: jasmussen <joen@git.wordpress.org>
Co-authored-by: kevin940726 <kevin940726@git.wordpress.org>
Co-authored-by: ironprogrammer <ironprogrammer@git.wordpress.org>
Co-authored-by: annezazu <annezazu@git.wordpress.org>
---
 .../__experimental-fetch-link-suggestions.ts  | 25 +++++++++++--
 .../__experimental-fetch-link-suggestions.js  | 37 +++++++++++++++++++
 2 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/packages/core-data/src/fetch/__experimental-fetch-link-suggestions.ts b/packages/core-data/src/fetch/__experimental-fetch-link-suggestions.ts
index e1a166ee272db..2901219758903 100644
--- a/packages/core-data/src/fetch/__experimental-fetch-link-suggestions.ts
+++ b/packages/core-data/src/fetch/__experimental-fetch-link-suggestions.ts
@@ -270,12 +270,29 @@ export function sortResults( results: SearchResult[], search: string ) {
 	for ( const result of results ) {
 		if ( result.title ) {
 			const titleTokens = tokenize( result.title );
-			const matchingTokens = titleTokens.filter( ( titleToken ) =>
-				searchTokens.some( ( searchToken ) =>
-					titleToken.includes( searchToken )
+			const exactMatchingTokens = titleTokens.filter( ( titleToken ) =>
+				searchTokens.some(
+					( searchToken ) => titleToken === searchToken
 				)
 			);
-			scores[ result.id ] = matchingTokens.length / titleTokens.length;
+			const subMatchingTokens = titleTokens.filter( ( titleToken ) =>
+				searchTokens.some(
+					( searchToken ) =>
+						titleToken !== searchToken &&
+						titleToken.includes( searchToken )
+				)
+			);
+
+			// The score is a combination of exact matches and sub-matches.
+			// More weight is given to exact matches, as they are more relevant (e.g. "cat" vs "caterpillar").
+			// Diving by the total number of tokens in the title normalizes the score and skews
+			// the results towards shorter titles.
+			const exactMatchScore =
+				( exactMatchingTokens.length / titleTokens.length ) * 10;
+
+			const subMatchScore = subMatchingTokens.length / titleTokens.length;
+
+			scores[ result.id ] = exactMatchScore + subMatchScore;
 		} else {
 			scores[ result.id ] = 0;
 		}
diff --git a/packages/core-data/src/fetch/test/__experimental-fetch-link-suggestions.js b/packages/core-data/src/fetch/test/__experimental-fetch-link-suggestions.js
index 6878c74332c3d..ad0014ff86ecb 100644
--- a/packages/core-data/src/fetch/test/__experimental-fetch-link-suggestions.js
+++ b/packages/core-data/src/fetch/test/__experimental-fetch-link-suggestions.js
@@ -393,6 +393,43 @@ describe( 'sortResults', () => {
 			6,
 		] );
 	} );
+
+	it( 'orders results to prefer direct matches over sub matches', () => {
+		const results = [
+			{
+				id: 1,
+				title: 'News',
+				url: 'http://wordpress.local/news/',
+				type: 'page',
+				kind: 'post-type',
+			},
+			{
+				id: 2,
+				title: 'Newspaper',
+				url: 'http://wordpress.local/newspaper/',
+				type: 'page',
+				kind: 'post-type',
+			},
+			{
+				id: 3,
+				title: 'News Flash News',
+				url: 'http://wordpress.local/news-flash-news/',
+				type: 'page',
+				kind: 'post-type',
+			},
+			{
+				id: 4,
+				title: 'News',
+				url: 'http://wordpress.local/news-2/',
+				type: 'page',
+				kind: 'post-type',
+			},
+		];
+		const order = sortResults( results, 'News' ).map(
+			( result ) => result.id
+		);
+		expect( order ).toEqual( [ 1, 4, 3, 2 ] );
+	} );
 } );
 
 describe( 'tokenize', () => {