fix(autocomplete): gracefully handle missing values when parsing highlights

packages/autocomplete-client/__tests__/test.utils.ts

@@ -26,6 +26,10 @@ export const MOVIES = [
     genres: ['Drama', 'Crime', 'Comedy'],
     poster: 'https://image.tmdb.org/t/p/w500/ojDg0PGvs6R9xYFodRct2kdI6wC.jpg',
     release_date: 593395200,
+    reviews: [
+      { id: 1, author: 'John', content: 'one star' },
+      { id: 2, author: 'Jane', content: 'two stars' },
+    ],
   },
   {
     id: 5,
@@ -35,6 +39,10 @@ export const MOVIES = [
     genres: ['Crime', 'Comedy'],
     poster: 'https://image.tmdb.org/t/p/w500/75aHn1NOYXh4M7L5shoeQ6NGykP.jpg',
     release_date: 818467200,
+    reviews: [
+      { id: 3, author: 'John', content: 'three stars' },
+      { id: 4, author: 'Jane', content: 'four stars' },
+    ],
   },
   {
     id: 6,
@@ -44,6 +52,10 @@ export const MOVIES = [
     genres: ['Action', 'Thriller', 'Crime'],
     poster: 'https://image.tmdb.org/t/p/w500/rYFAvSPlQUCebayLcxyK79yvtvV.jpg',
     release_date: 750643200,
+    reviews: [
+      { id: 5, author: 'John', content: 'five stars' },
+      { id: 6, author: 'Jane', content: 'six stars' },
+    ],
   },
   {
     id: 11,
@@ -53,6 +65,10 @@ export const MOVIES = [
     genres: ['Adventure', 'Action', 'Science Fiction'],
     poster: 'https://image.tmdb.org/t/p/w500/6FfCtAuVAW8XJjZ7eWeLibRLWTw.jpg',
     release_date: 233366400,
+    reviews: [
+      { id: 7, author: 'John', content: 'seven stars' },
+      { id: 8, author: 'Jane', content: 'eight stars' },
+    ],
   },
   {
     id: 30,
@@ -61,6 +77,10 @@ export const MOVIES = [
     genres: ['Animation', 'Science Fiction'],
     poster: 'https://image.tmdb.org/t/p/w500/gSuHDeWemA1menrwfMRChnSmMVN.jpg',
     release_date: 819676800,
+    reviews: [
+      { id: 9, author: 'John', content: 'nine stars' },
+      { id: 10, author: 'Jane', content: 'ten stars' },
+    ],
   },
   {
     id: 24,
@@ -69,6 +89,10 @@ export const MOVIES = [
     genres: ['Action', 'Crime'],
     poster: 'https://image.tmdb.org/t/p/w500/v7TaX8kXMXs5yFFGR41guUDNcnB.jpg',
     release_date: 1065744000,
+    reviews: [
+      { id: 11, author: 'John', content: 'eleven stars' },
+      { id: 12, author: 'Jane', content: 'twelve stars' },
+    ],
   },
 ]
 

packages/autocomplete-client/src/search/__tests__/fetchMeilisearchResults.test.ts

@@ -184,4 +184,18 @@ describe('fetchMeilisearchResults', () => {
       matchedWords: [],
     })
   })
+
+  test('highlight results skips attributes missing value key', async () => {
+    const results = await fetchMeilisearchResults({
+      searchClient,
+      queries: [
+        {
+          indexName: INDEX_NAME,
+          query: 'kill bill',
+        },
+      ],
+    })
+
+    expect(results[0].hits[0]._highlightResult?.reviews).toEqual(undefined)
+  })
 })

packages/autocomplete-client/src/search/fetchMeilisearchResults.ts

@@ -64,22 +64,27 @@ export function fetchMeilisearchResults<TRecord = Record<string, any>>({
                 ...hit,
                 _highlightResult: (
                   Object.entries(hit?._highlightResult || {}) as Array<
-                    | [keyof TRecord, { value: string }]
-                    | [keyof TRecord, Array<{ value: string }>] // if the field is an array
+                    [keyof TRecord, PossibleHighlightResult]
                   >
                 ).reduce((acc, [field, highlightResult]) => {
-                  return {
-                    ...acc,
-                    // if the field is an array, highlightResult is an array of objects
-                    [field]: mapOneOrMany(highlightResult, (highlightResult) =>
-                      calculateHighlightMetadata(
+                  if (!isDefinedHighlightValue(highlightResult)) {
+                    return acc
+                  }
+
+                  // if the field is an array, highlightResult is an array of objects
+                  acc[field] = mapOneOrMany(
+                    highlightResult,
+                    (highlightResult) => {
+                      return calculateHighlightMetadata(
                         query.query || '',
                         query.params?.highlightPreTag || HIGHLIGHT_PRE_TAG,
                         query.params?.highlightPostTag || HIGHLIGHT_POST_TAG,
                         highlightResult.value
                       )
-                    ),
-                  }
+                    }
+                  )
+
+                  return acc
                 }, {} as HighlightResult<TRecord>),
               })),
             }
@@ -144,3 +149,26 @@ function calculateHighlightMetadata(
 function mapOneOrMany<T, U>(value: T | T[], mapFn: (value: T) => U): U | U[] {
   return Array.isArray(value) ? value.map(mapFn) : mapFn(value)
 }
+
+type DefinedHighlightResult = { value: string } | Array<{ value: string }> // if the field is an array
+
+/**
+ * Some fields may not return a value at all - nested arrays/objects for example
+ *
+ * Ideally server honours the `attributesToHighlight` param and only includes
+ * those attributes in the response rather than all attributes (highlighted or
+ * not)
+ */
+type UndefinedHighlightResult = { value?: never } | Array<{ value?: never }>
+
+type PossibleHighlightResult = DefinedHighlightResult | UndefinedHighlightResult
+
+function isDefinedHighlightValue(
+  input: PossibleHighlightResult
+): input is DefinedHighlightResult {
+  if (Array.isArray(input)) {
+    return input.every((r) => typeof r.value === 'string')
+  }
+
+  return typeof input.value === 'string'
+}