Port mentions resolvers to TypeScript

src/utils/chatMentions.ts

@@ -0,0 +1,80 @@
+import type { MarkupNode, MentionNode } from 'u-wave-parse-chat-markup';
+import { userListSelector, type User } from '../reducers/users';
+import type { StoreState } from '../redux/configureStore';
+import * as groupMentions from './groupMentions';
+
+export { groupMentions };
+
+/** Get a list of group names that can be mentioned by a user. */
+export function getAvailableGroupMentions(canMention: (group: string) => boolean) {
+  if (canMention) {
+    return Object.keys(groupMentions).filter(canMention);
+  }
+  return [];
+}
+
+const groupTag = Symbol('group');
+const userTag = Symbol('user');
+function tagWithGroup(node: MentionNode, group: Set<string>) {
+  Object.defineProperty(node, groupTag, { value: group });
+}
+function tagWithUser(node: MentionNode, user: User) {
+  Object.defineProperty(node, userTag, { value: user });
+}
+
+function taggedGroup(node: MentionNode): Set<string> | undefined {
+  return (node as Record<symbol, Set<string>>)[groupTag];
+}
+function taggedUser(node: MentionNode): User | undefined {
+  return (node as Record<symbol, User>)[userTag];
+}
+
+/** Attach user objects to mentions in a parsed chat message. */
+export function resolveMentions(tree: MarkupNode[], state: StoreState) {
+  const users = userListSelector(state);
+  tree.forEach((node) => {
+    if (typeof node === 'string') {
+      // No mentions in plain text :)
+    } else if (node.type === 'mention') {
+      const groupSelector = node.mention in groupMentions
+        ? groupMentions[node.mention as keyof typeof groupMentions]
+        : null;
+      /* eslint-disable no-param-reassign */
+      if (groupSelector != null) {
+        const group = groupSelector(state).filter((user) => user != null);
+        if (group.length > 0) {
+          tagWithGroup(node, new Set(group.map((user) => user._id)));
+        }
+      } else {
+        const mentionedUser = users.find((user) => user.username.toLowerCase() === node.mention);
+        if (mentionedUser != null) {
+          tagWithUser(node, mentionedUser);
+        }
+      }
+      /* eslint-enable no-param-reassign */
+    } else if ('content' in node) {
+      resolveMentions(node.content, state);
+    }
+  });
+}
+
+/**
+ * Check whether a parsed chat message mentions a given user ID. Expects mention
+ * nodes to have User data, added by `resolveMentions()`.
+ */
+export function hasMention(tree: MarkupNode[], userID: string): boolean {
+  return tree.some((node) => {
+    if (typeof node === 'object' && node.type === 'mention') {
+      const user = taggedUser(node);
+      if (user != null) {
+        return user._id === userID;
+      }
+      const group = taggedGroup(node);
+      if (group != null) {
+        return group.has(userID);
+      }
+      return false;
+    }
+    return Array.isArray(node) && hasMention(node, userID);
+  });
+}

src/utils/groupMentions.js → src/utils/groupMentions.ts

@@ -1,13 +1,14 @@
 import { userListSelector, userHasRoleSelector } from '../reducers/users';
 import { djAndWaitlistUsersSelector } from '../reducers/waitlist';
+import type { StoreState } from '../redux/configureStore';
 
 export const everyone = userListSelector;
 
 // plug.dj-like.
 export const djs = djAndWaitlistUsersSelector;
 export const waitlist = djs;
 
-export function staff(state) {
+export function staff(state: StoreState) {
   const users = userListSelector(state);
   return users.filter((user) => {
     // TODO should this maybe not hardcode the 'moderator' role? How to do it