feat: Add the ability to parse markdown and replace tags asynchronously, and fetch the missing users and channels.

package.json

@@ -32,7 +32,7 @@
     "json-with-bigint": "^3.4.4",
     "solid-js": "^1.9.6",
     "stoat-api": "0.8.9-4",
-    "ulid": "^2.4.0"
+    "ulid": "^3.0.2"
   },
   "devDependencies": {
     "@mxssfd/typedoc-theme": "^1.1.7",

src/Client.ts

@@ -34,7 +34,12 @@ import type { HydratedMessage } from "./hydration/message.js";
 import type { HydratedServer } from "./hydration/server.js";
 import type { HydratedServerMember } from "./hydration/serverMember.js";
 import type { HydratedUser } from "./hydration/user.js";
-import { RE_CHANNELS, RE_MENTIONS, RE_SPOILER } from "./lib/regex.js";
+import {
+  RE_CHANNELS,
+  RE_CUSTOM_EMOJI,
+  RE_MENTIONS,
+  RE_SPOILER,
+} from "./lib/regex.js";
 
 export type Session = { _id: string; token: string; user_id: string } | string;
 
@@ -242,7 +247,9 @@ export class Client extends AsyncEventEmitter<Events> {
       baseURL: this.options.baseURL,
     });
 
-    const [configured, setConfigured] = createSignal(configuration !== undefined);
+    const [configured, setConfigured] = createSignal(
+      configuration !== undefined,
+    );
     this.configured = configured;
     this.#setConfigured = setConfigured;
 
@@ -416,6 +423,97 @@ export class Client extends AsyncEventEmitter<Events> {
       .replace(RE_SPOILER, "<spoiler>");
   }
 
+  /**
+   * Prepare a markdown-based message to be displayed to the user as plain text. This method will fetch each user or channel if they are missing. Useful for serviceworkers.
+   * @param source Source markdown text
+   * @returns Modified plain text
+   */
+  async markdownToTextFetch(source: string): Promise<string> {
+    // Get all user matches, create a map to dedupe
+    const userMatches = Object.fromEntries(
+      Array.from(source.matchAll(RE_MENTIONS), (match) => {
+        return [match[0], match[1]];
+      }),
+    );
+
+    // Get all channel matches, create a map to dedupe
+    const channelMatches = Object.fromEntries(
+      Array.from(source.matchAll(RE_CHANNELS), (match) => {
+        return [match[0], match[1]];
+      }),
+    );
+
+    // Get all custom emoji matches, create a map to dedupe
+    const customEmojiMatches = Object.fromEntries(
+      Array.from(source.matchAll(RE_CUSTOM_EMOJI), (match) => {
+        return [match[0], match[1]];
+      }),
+    );
+
+    // Send requests to replace user ids
+    const userReplacementPromises = Object.keys(userMatches).map(
+      async (key) => {
+        const substr = userMatches[key];
+        if (substr) {
+          const user = await this.users.fetch(substr);
+
+          if (user) {
+            return [key, `@${user.username}`];
+          }
+        }
+
+        return [key, key];
+      },
+    );
+
+    // Send requests to replace channel ids
+    const channelReplacementPromises = Object.keys(channelMatches).map(
+      async (key) => {
+        const substr = channelMatches[key];
+        if (substr) {
+          const channel = await this.channels.fetch(substr);
+
+          if (channel) {
+            return [key, `#${channel.displayName}`];
+          }
+        }
+
+        return [key, key];
+      },
+    );
+
+    // Send requests to replace custom emojis
+    const customEmojiReplacementPromises = Object.keys(customEmojiMatches).map(
+      async (key) => {
+        const substr = customEmojiMatches[key];
+        if (substr) {
+          const emoji = await this.emojis.fetch(substr);
+
+          if (emoji) {
+            return [key, `:${emoji.name}:`];
+          }
+        }
+
+        return [key, key];
+      },
+    );
+
+    // Await for all promises to get the strings to replace with.
+    const replacements = await Promise.all([
+      ...userReplacementPromises,
+      ...channelReplacementPromises,
+      ...customEmojiReplacementPromises,
+    ]);
+
+    const replacementsMap = Object.fromEntries(replacements);
+
+    return source
+      .replace(RE_MENTIONS, (match) => replacementsMap[match])
+      .replace(RE_CHANNELS, (match) => replacementsMap[match])
+      .replace(RE_CUSTOM_EMOJI, (match) => replacementsMap[match])
+      .replace(RE_SPOILER, "<spoiler>");
+  }
+
   /**
    * Proxy a file through January.
    * @param url URL to proxy

src/lib/regex.ts

@@ -8,6 +8,11 @@ export const RE_MENTIONS = /<@([0-9ABCDEFGHJKMNPQRSTVWXYZ]{26})>/g;
  */
 export const RE_CHANNELS = /<#([0-9ABCDEFGHJKMNPQRSTVWXYZ]{26})>/g;
 
+/**
+ * Regular expression for stripping custom emojis.
+ */
+export const RE_CUSTOM_EMOJI = /:([0-9ABCDEFGHJKMNPQRSTVWXYZ]{26}):/g;
+
 /**
  * Regular expression for spoilers.
  */