user autocomplete: Use uniq to deduplicate items that match multiple ways

See zulip#5508 (comment)

Author: chrisbobbe

package.json

@@ -51,7 +51,7 @@
     "lodash.isequal": "^4.4.0",
     "lodash.omit": "^4.5.0",
     "lodash.union": "^4.6.0",
-    "lodash.uniqby": "^4.4.0",
+    "lodash.uniq": "^4.5.0",
     "react": "17.0.2",
     "react-intl": "5.24.6",
     "react-native": "0.67.4",

src/users/__tests__/userHelpers-test.js

@@ -10,7 +10,6 @@ import {
   filterUserStartWith,
   filterUserThatContains,
   filterUserMatchesEmail,
-  getUniqueUsers,
   groupUsersByStatus,
 } from '../userHelpers';
 import * as eg from '../../__tests__/lib/exampleData';
@@ -99,7 +98,7 @@ describe('getAutocompleteSuggestion', () => {
     const user5 = eg.makeUser({ full_name: 'match', email: '[email protected]' }); // satisfy full_name starts with condition
     const user6 = eg.makeUser({ full_name: 'match', email: '[email protected]' }); // satisfy starts with and email condition
     const user7 = eg.makeUser({ full_name: 'Match App Normal', email: '[email protected]' }); // satisfy all conditions
-    const user8 = eg.makeUser({ full_name: 'match', email: '[email protected]' }); // duplicate
+    const user8 = user5; // duplicate
     const user9 = eg.makeUser({ full_name: 'Laptop', email: '[email protected]' }); // random entry
     const user10 = eg.makeUser({ full_name: 'Mobile App', email: '[email protected]' }); // satisfy email condition
     const user11 = eg.makeUser({ full_name: 'Normal', email: '[email protected]' }); // satisfy contains in name and matches in email condition
@@ -342,21 +341,3 @@ describe('filterUserMatchesEmail', () => {
     expect(filterUserMatchesEmail(users, 'example', selfUser.user_id)).toEqual(expectedUsers);
   });
 });
-
-describe('getUniqueUsers', () => {
-  test('returns unique users check by email', () => {
-    const user1 = eg.makeUser({ email: '[email protected]' });
-    const user2 = eg.makeUser({ email: '[email protected]' });
-    const user3 = eg.makeUser({ email: '[email protected]' });
-    const user4 = eg.makeUser({ email: '[email protected]' });
-    const user5 = eg.makeUser({ email: '[email protected]' });
-    const user6 = eg.makeUser({ email: '[email protected]' });
-    const user7 = eg.makeUser({ email: '[email protected]' });
-    const user8 = eg.makeUser({ email: '[email protected]' });
-
-    const users = deepFreeze([user1, user2, user3, user4, user5, user6, user7, user8]);
-
-    const expectedUsers = [user1, user3, user5, user8];
-    expect(getUniqueUsers(users)).toEqual(expectedUsers);
-  });
-});

src/users/userHelpers.js

@@ -1,6 +1,6 @@
 /* @flow strict-local */
 // $FlowFixMe[untyped-import]
-import uniqby from 'lodash.uniqby';
+import uniq from 'lodash.uniq';
 import * as typeahead from '@zulip/shared/js/typeahead';
 
 import type {
@@ -104,9 +104,11 @@ export const filterUserMatchesEmail = (
     user => user.user_id !== ownUserId && user.email.toLowerCase().includes(filter.toLowerCase()),
   );
 
-export const getUniqueUsers = (users: $ReadOnlyArray<UserOrBot>): $ReadOnlyArray<UserOrBot> =>
-  uniqby(users, 'email');
-
+/**
+ * Get the list of users for a user-autocomplete query.
+ *
+ * Callers must ensure that `users` has just one unique object per user ID.
+ */
 export const getAutocompleteSuggestion = (
   users: $ReadOnlyArray<UserOrBot>,
   filter: string,
@@ -119,7 +121,16 @@ export const getAutocompleteSuggestion = (
   const startWith = filterUserStartWith(users, filter, ownUserId);
   const contains = filterUserThatContains(users, filter, ownUserId);
   const matchesEmail = filterUserMatchesEmail(users, filter, ownUserId);
-  const candidates = getUniqueUsers([...startWith, ...contains, ...matchesEmail]);
+
+  // Dedupe users that match in multiple ways.
+  const candidates: $ReadOnlyArray<UserOrBot> =
+    // Lodash's "unique" is just as good as "unique by user ID" as long as
+    // there aren't multiple unique objects per user ID. See doc:
+    //   https://lodash.com/docs/4.17.15#uniq
+    // So we ask the caller to satisfy that for `users`; then when we
+    // deduplicate, here, we only pass objects that appear in `users`.
+    uniq([...startWith, ...contains, ...matchesEmail]);
+
   return candidates.filter(user => !mutedUsers.has(user.user_id));
 };
 

yarn.lock

@@ -10541,11 +10541,6 @@ lodash.uniq@^4.5.0:
   resolved "https://registry.yarnpkg.com/lodash.uniq/-/lodash.uniq-4.5.0.tgz#d0225373aeb652adc1bc82e4945339a842754773"
   integrity sha512-xfBaXQd9ryd9dlSDvnvI0lvxfLJlYAZzXomUYzLKtUeOQvOP5piqAWuGtrhWeqaXK9hhoM/iyJc5AV+XfsX3HQ==
 
-lodash.uniqby@^4.4.0:
-  version "4.7.0"
-  resolved "https://registry.yarnpkg.com/lodash.uniqby/-/lodash.uniqby-4.7.0.tgz#d99c07a669e9e6d24e1362dfe266c67616af1302"
-  integrity sha512-e/zcLx6CSbmaEgFHCA7BnoQKyCtKMxnuWrJygbwPs/AIn+IMKl66L8/s+wBUn5LRw2pZx3bUHibiV1b6aTWIww==
-
 "lodash@>=3.5 <5", lodash@^4.17.10, lodash@^4.17.11, lodash@^4.17.12, lodash@^4.17.13, lodash@^4.17.14, lodash@^4.17.15, lodash@^4.17.19, lodash@^4.17.20, lodash@^4.17.21, lodash@^4.17.4, lodash@^4.17.5, lodash@^4.7.0:
   version "4.17.21"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"