typeahead: Add typescript type definitions for typeahead.

This allows us to import typeahead from people.ts with types. This is
possible since #22586 was merged.

And since "sort_emojis" is always supposed to be called with valid emoji
objects that have "reaction_type" with an optional "emoji_code", we add
a check before we see if the emoji is popular to avoid poking
popular_set with an undefined value.

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

static/shared/js/typeahead.ts

@@ -28,7 +28,23 @@ export const popular_emojis = [
 
 const unicode_marks = /\p{M}/gu;
 
-export function remove_diacritics(s) {
+type Emoji =
+    | {
+          emoji_name: string;
+          reaction_type: "realm_emoji" | "zulip_extra_emoji";
+          is_realm_emoji: true;
+      }
+    | UnicodeEmoji;
+
+// emoji_code is only available for unicode emojis.
+type UnicodeEmoji = {
+    emoji_name: string;
+    emoji_code: string;
+    reaction_type: "unicode_emoji";
+    is_realm_emoji: false;
+};
+
+export function remove_diacritics(s: string): string {
     return s.normalize("NFKD").replace(unicode_marks, "");
 }
 
@@ -36,7 +52,11 @@ export function remove_diacritics(s) {
 // * query is the user-entered search query
 // * source_str is the string we're matching in, e.g. a user's name
 // * split_char is the separator for this syntax (e.g. ' ').
-export function query_matches_string(query, source_str, split_char) {
+export function query_matches_string(
+    query: string,
+    source_str: string,
+    split_char: string,
+): boolean {
     source_str = source_str.toLowerCase();
     source_str = remove_diacritics(source_str);
 
@@ -53,7 +73,7 @@ export function query_matches_string(query, source_str, split_char) {
     return source_str.startsWith(query) || source_str.includes(split_char + query);
 }
 
-function clean_query(query) {
+function clean_query(query: string): string {
     query = remove_diacritics(query);
     // When `abc ` with a space at the end is typed in a
     // contenteditable widget such as the composebox PM section, the
@@ -64,19 +84,19 @@ function clean_query(query) {
     return query;
 }
 
-export function clean_query_lowercase(query) {
+export function clean_query_lowercase(query: string): string {
     query = query.toLowerCase();
     query = clean_query(query);
     return query;
 }
 
-export const parse_unicode_emoji_code = (code) =>
+export const parse_unicode_emoji_code = (code: string): string =>
     code
         .split("-")
         .map((hex) => String.fromCodePoint(Number.parseInt(hex, 16)))
         .join("");
 
-export function get_emoji_matcher(query) {
+export function get_emoji_matcher(query: string): (emoji: Emoji) => boolean {
     // replace spaces with underscores for emoji matching
     query = query.replace(/ /g, "_");
     query = clean_query_lowercase(query);
@@ -89,7 +109,11 @@ export function get_emoji_matcher(query) {
     };
 }
 
-export function triage(query, objs, get_item) {
+export function triage<T>(
+    query: string,
+    objs: T[],
+    get_item: (x: T) => string,
+): {matches: T[]; rest: T[]} {
     /*
         We split objs into four groups:
 
@@ -128,20 +152,24 @@ export function triage(query, objs, get_item) {
     };
 }
 
-export function sort_emojis(objs, query) {
+export function sort_emojis<T extends Emoji>(objs: T[], query: string): T[] {
     // replace spaces with underscores for emoji matching
     query = query.replace(/ /g, "_");
     query = query.toLowerCase();
 
-    function decent_match(name) {
+    function decent_match(name: string): boolean {
         const pieces = name.toLowerCase().split("_");
         return pieces.some((piece) => piece.startsWith(query));
     }
 
     const popular_set = new Set(popular_emojis);
 
-    function is_popular(obj) {
-        return popular_set.has(obj.emoji_code) && decent_match(obj.emoji_name);
+    function is_popular(obj: Emoji): boolean {
+        return (
+            obj.reaction_type === "unicode_emoji" &&
+            popular_set.has(obj.emoji_code) &&
+            decent_match(obj.emoji_name)
+        );
     }
 
     const realm_emoji_names = new Set(
@@ -153,7 +181,7 @@ export function sort_emojis(objs, query) {
 
     const triage_results = triage(query, others, (x) => x.emoji_name);
 
-    function prioritise_realm_emojis(emojis) {
+    function prioritise_realm_emojis(emojis: T[]): T[] {
         return [
             ...emojis.filter((emoji) => emoji.is_realm_emoji),
             ...emojis.filter((emoji) => !emoji.is_realm_emoji),
@@ -168,7 +196,7 @@ export function sort_emojis(objs, query) {
     // remove unicode emojis with same code but different names
     // and unicode emojis overridden by realm emojis with same names
     const unicode_emoji_codes = new Set();
-    const sorted_unique_results = [];
+    const sorted_unique_results: T[] = [];
     for (const emoji of sorted_results_with_possible_duplicates) {
         if (emoji.reaction_type !== "unicode_emoji") {
             sorted_unique_results.push(emoji);