[Refactoring] Remove flatten, add generic type for split (#1879)

src/api/gramjs/apiBuilders/misc.ts

@@ -7,7 +7,7 @@ import { ApiPrivacySettings, ApiPrivacyKey, PrivacyVisibility } from '../../../t
 
 import { buildApiDocument } from './messages';
 import { buildApiPeerId, getApiChatIdFromMtpPeer } from './peers';
-import { flatten, pick } from '../../../util/iteratees';
+import { pick } from '../../../util/iteratees';
 import { getServerTime } from '../../../util/serverTime';
 
 export function buildApiWallpaper(wallpaper: GramJs.TypeWallPaper): ApiWallpaper | undefined {
@@ -124,7 +124,7 @@ export function buildApiNotifyException(
   };
 }
 
-function buildApiCountry(country: GramJs.help.Country, code?: GramJs.help.CountryCode) {
+function buildApiCountry(country: GramJs.help.Country, code: GramJs.help.CountryCode) {
   const {
     hidden, iso2, defaultName, name,
   } = country;
@@ -142,20 +142,18 @@ function buildApiCountry(country: GramJs.help.Country, code?: GramJs.help.Countr
 }
 
 export function buildApiCountryList(countries: GramJs.help.Country[]) {
-  const listByCode = flatten(
-    countries
-      .filter((country) => !country.hidden)
-      .map((country) => (
-        country.countryCodes.map((code) => buildApiCountry(country, code))
-      )),
-  )
+  const nonHiddenCountries = countries.filter(({ hidden }) => !hidden);
+  const listByCode = nonHiddenCountries
+    .map((country) => (
+      country.countryCodes.map((code) => buildApiCountry(country, code))
+    ))
+    .flat()
     .sort((a: ApiCountry, b: ApiCountry) => (
       a.name ? a.name.localeCompare(b.name!) : a.defaultName.localeCompare(b.defaultName)
     ));
 
-  const generalList = countries
-    .filter((country) => !country.hidden)
-    .map((country) => buildApiCountry(country))
+  const generalList = nonHiddenCountries
+    .map((country) => buildApiCountry(country, country.countryCodes[0]))
     .sort((a, b) => (
       a.name ? a.name.localeCompare(b.name!) : a.defaultName.localeCompare(b.defaultName)
     ));

src/components/middle/MessageListContent.tsx

@@ -5,7 +5,7 @@ import { MessageListType } from '../../global/types';
 
 import { SCHEDULED_WHEN_ONLINE } from '../../config';
 import buildClassName from '../../util/buildClassName';
-import { compact, flatten } from '../../util/iteratees';
+import { compact } from '../../util/iteratees';
 import { formatHumanDate } from '../../util/dateFormat';
 import {
   getMessageHtmlId, getMessageOriginalId, isActionMessage, isOwnMessage,
@@ -108,7 +108,7 @@ const MessageListContent: FC<OwnProps> = ({
   );
 
   const messageCountToAnimate = noAppearanceAnimation ? 0 : messageGroups.reduce((acc, messageGroup) => {
-    return acc + flatten(messageGroup.senderGroups).length;
+    return acc + messageGroup.senderGroups.flat().length;
   }, 0);
   let appearanceIndex = 0;
 
@@ -148,7 +148,7 @@ const MessageListContent: FC<OwnProps> = ({
 
       let currentDocumentGroupId: string | undefined;
 
-      return flatten(senderGroup.map((
+      return senderGroup.map((
         messageOrAlbum,
         messageIndex,
       ) => {
@@ -214,7 +214,7 @@ const MessageListContent: FC<OwnProps> = ({
             </div>
           ),
         ]);
-      }));
+      }).flat();
     });
 
     return (
@@ -240,7 +240,7 @@ const MessageListContent: FC<OwnProps> = ({
             {!isSchedule && formatHumanDate(lang, dateGroup.datetime)}
           </span>
         </div>
-        {flatten(senderGroups)}
+        {senderGroups.flat()}
       </div>
     );
   });
@@ -248,7 +248,7 @@ const MessageListContent: FC<OwnProps> = ({
   return (
     <div className="messages-container" teactFastList>
       <div ref={backwardsTriggerRef} key="backwards-trigger" className="backwards-trigger" />
-      {flatten(dateGroups)}
+      {dateGroups.flat()}
       {isViewportNewest && <SponsoredMessage key={chatId} chatId={chatId} containerRef={containerRef} />}
       <div
         ref={forwardsTriggerRef}

src/components/middle/composer/hooks/useEmojiTooltip.ts

@@ -10,7 +10,7 @@ import {
 } from '../../../../util/emoji';
 import focusEditableElement from '../../../../util/focusEditableElement';
 import {
-  buildCollectionByKey, flatten, mapValues, pickTruthy, unique,
+  buildCollectionByKey, mapValues, pickTruthy, unique,
 } from '../../../../util/iteratees';
 import memoized from '../../../../util/memoized';
 import useFlag from '../../../../hooks/useFlag';
@@ -222,11 +222,11 @@ function searchInLibrary(library: Library, filter: string, limit: number) {
   let matched: Emoji[] = MEMO_EMPTY_ARRAY;
 
   const matchedKeywords = keywords.filter((keyword) => keyword.startsWith(filter)).sort();
-  matched = matched.concat(flatten(Object.values(pickTruthy(byKeyword!, matchedKeywords))));
+  matched = matched.concat(Object.values(pickTruthy(byKeyword!, matchedKeywords)).flat());
 
   // Also search by names, which is useful for non-English languages
   const matchedNames = names.filter((name) => name.startsWith(filter));
-  matched = matched.concat(flatten(Object.values(pickTruthy(byName, matchedNames))));
+  matched = matched.concat(Object.values(pickTruthy(byName, matchedNames)).flat());
 
   matched = unique(matched);
 

src/global/actions/api/messages.ts

@@ -228,7 +228,7 @@ addActionHandler('sendMessage', (global, actions, payload) => {
     const {
       text, entities, attachments, ...commonParams
     } = params;
-    const groupedAttachments = split(attachments, MAX_MEDIA_FILES_FOR_ALBUM);
+    const groupedAttachments = split(attachments as ApiAttachment[], MAX_MEDIA_FILES_FOR_ALBUM);
     for (let i = 0; i < groupedAttachments.length; i++) {
       const [firstAttachment, ...restAttachments] = groupedAttachments[i];
       const groupedId = `${Date.now()}${i}`;

src/lib/teact/teact.ts

@@ -3,7 +3,7 @@ import { DEBUG, DEBUG_MORE } from '../../config';
 import {
   fastRaf, fastRafPrimary, onTickEnd, onTickEndPrimary, throttleWithPrimaryRaf, throttleWithRaf,
 } from '../../util/schedulers';
-import { flatten, orderBy } from '../../util/iteratees';
+import { orderBy } from '../../util/iteratees';
 import { getUnequalProps } from '../../util/arePropsShallowEqual';
 import { handleError } from '../../util/handleError';
 import { removeAllDelegatedListeners } from './dom-events';
@@ -143,7 +143,7 @@ function createElement(
     props = {};
   }
 
-  children = flatten(children);
+  children = children.flat();
 
   if (source === Fragment) {
     return children;

src/util/iteratees.ts

@@ -80,17 +80,6 @@ export function orderBy<T>(
   });
 }
 
-export function flatten(array: any[]) {
-  return array.reduce((result, member) => {
-    if (Array.isArray(member)) {
-      return result.concat(member);
-    } else {
-      result.push(member);
-      return result;
-    }
-  }, []);
-}
-
 export function unique<T extends any>(array: T[]): T[] {
   return Array.from(new Set(array));
 }
@@ -115,8 +104,8 @@ export function findIntersectionWithSet<T>(array: T[], set: Set<T>): T[] {
   return array.filter((a) => set.has(a));
 }
 
-export function split(array: any[], chunkSize: number) {
-  const result = [];
+export function split<T extends any>(array: T[], chunkSize: number) {
+  const result: T[][] = [];
   for (let i = 0; i < array.length; i += chunkSize) {
     result.push(array.slice(i, i + chunkSize));
   }

src/util/phoneNumber.ts

@@ -1,5 +1,4 @@
 import { ApiCountryCode } from '../api/types';
-import { flatten } from './iteratees';
 
 const PATTERN_PLACEHOLDER = 'X';
 const DEFAULT_PATTERN = 'XXX XXX XXX XXX';
@@ -16,13 +15,14 @@ export function getCountryFromPhoneNumber(phoneCodeList: ApiCountryCode[], input
 
   const possibleCountries = phoneCodeList
     .filter((country) => phoneNumber.startsWith(country.countryCode));
-  const codesWithPrefix: { code: string; country: ApiCountryCode }[] = flatten(possibleCountries
+  const codesWithPrefix: { code: string; country: ApiCountryCode }[] = possibleCountries
     .map((country) => (country.prefixes || ['']).map((prefix) => {
       return {
         code: `${country.countryCode}${prefix}`,
         country,
       };
-    })));
+    }))
+    .flat();
 
   const bestMatches = codesWithPrefix
     .filter(({ code }) => phoneNumber.startsWith(code))