DEV: Add registerCustomLastUnreadUrlCallbackto plugin API (#16222)

app/assets/javascripts/discourse/app/lib/plugin-api.js

@@ -84,6 +84,7 @@ import { registerTopicFooterDropdown } from "discourse/lib/register-topic-footer
 import { registerDesktopNotificationHandler } from "discourse/lib/desktop-notifications";
 import { replaceFormatter } from "discourse/lib/utilities";
 import { replaceTagRenderer } from "discourse/lib/render-tag";
+import { registerCustomLastUnreadUrlCallback } from "discourse/models/topic";
 import { setNewCategoryDefaultColors } from "discourse/routes/new-category";
 import { addSearchResultsCallback } from "discourse/lib/search";
 import {
@@ -98,7 +99,7 @@ import { consolePrefix } from "discourse/lib/source-identifier";
 // based on Semantic Versioning 2.0.0. Please update the changelog at
 // docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md whenever you change the version
 // using the format described at https://keepachangelog.com/en/1.0.0/.
-const PLUGIN_API_VERSION = "1.1.0";
+const PLUGIN_API_VERSION = "1.2.0";
 
 // This helper prevents us from applying the same `modifyClass` over and over in test mode.
 function canModify(klass, type, resolverName, changes) {
@@ -1290,6 +1291,21 @@ class PluginApi {
     replaceTagRenderer(fn);
   }
 
+  /**
+   * Register a custom last unread url for a topic list item.
+   * If a non-null value is returned, it will be used right away.
+   *
+   * Example:
+   *
+   * function testLastUnreadUrl(context) {
+   *   return context.urlForPostNumber(1);
+   * }
+   * api.registerCustomLastUnreadUrlCallback(testLastUnreadUrl);
+   **/
+  registerCustomLastUnreadUrlCallback(fn) {
+    registerCustomLastUnreadUrlCallback(fn);
+  }
+
   /**
    * Registers custom languages for use with HighlightJS.
    *

app/assets/javascripts/discourse/app/models/topic.js

@@ -41,6 +41,7 @@ export function loadTopicView(topic, args) {
 }
 
 export const ID_CONSTRAINT = /^\d+$/;
+let _customLastUnreadUrlCallbacks = [];
 
 const Topic = RestModel.extend({
   message: null,
@@ -256,6 +257,19 @@ const Topic = RestModel.extend({
 
   @discourseComputed("last_read_post_number", "highest_post_number", "url")
   lastUnreadUrl(lastReadPostNumber, highestPostNumber) {
+    let customUrl = null;
+    _customLastUnreadUrlCallbacks.some((cb) => {
+      const result = cb(this);
+      if (result) {
+        customUrl = result;
+        return true;
+      }
+    });
+
+    if (customUrl) {
+      return customUrl;
+    }
+
     if (highestPostNumber <= lastReadPostNumber) {
       if (this.get("category.navigate_to_first_post_after_read")) {
         return this.urlForPostNumber(1);
@@ -876,4 +890,13 @@ export function mergeTopic(topicId, data) {
   );
 }
 
+export function registerCustomLastUnreadUrlCallback(fn) {
+  _customLastUnreadUrlCallbacks.push(fn);
+}
+
+// Should only be used in tests
+export function clearCustomLastUnreadUrlCallbacks() {
+  _customLastUnreadUrlCallbacks.clear();
+}
+
 export default Topic;

app/assets/javascripts/discourse/tests/acceptance/topic-list-plugin-api-test.js

@@ -0,0 +1,29 @@
+import { acceptance, query } from "discourse/tests/helpers/qunit-helpers";
+import { clearCustomLastUnreadUrlCallbacks } from "discourse/models/topic";
+import { test } from "qunit";
+import { visit } from "@ember/test-helpers";
+import { withPluginApi } from "discourse/lib/plugin-api";
+
+acceptance("Topic list plugin API", function () {
+  function customLastUnreadUrl(context) {
+    return `${context.urlForPostNumber(1)}?overriden`;
+  }
+
+  test("Overrides lastUnreadUrl", async function (assert) {
+    try {
+      withPluginApi("1.2.0", (api) => {
+        api.registerCustomLastUnreadUrlCallback(customLastUnreadUrl);
+      });
+
+      await visit("/");
+      assert.strictEqual(
+        query(
+          ".topic-list .topic-list-item:first-child a.raw-topic-link"
+        ).getAttribute("href"),
+        "/t/error-after-upgrade-to-0-9-7-9/11557/1?overriden"
+      );
+    } finally {
+      clearCustomLastUnreadUrlCallbacks();
+    }
+  });
+});

docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md

@@ -2,20 +2,32 @@
 
 All notable changes to the Discourse JavaScript plugin API located at
 app/assets/javascripts/discourse/app/lib/plugin-api.js will be described
-in this file..
+in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [1.1.0] - 2021-12-15
+## [1.2.0] - 2022-03-18
+
 ### Added
+
+- Adds `registerCustomLastUnreadUrlCallback`, which allows users to register a custom
+  function that returns a last unread url for a topic list item. When multiple callbacks
+  are registered, the first non-null value that is returned will be used.
+
+## [1.1.0] - 2021-12-15
+
+### Added
+
 - Adds `addPosterIcons`, which allows users to add multiple icons to a poster. The
   addition of this function also makes the existing `addPosterIcon` now an alias to this
   function. Users may now just use `addPosterIcons` for both one or many icons. This
   function allows users to now return many icons depending on an `attrs`.
 
 ## [1.0.0] - 2021-11-25
+
 ### Removed
+
 - Removes the `addComposerUploadProcessor` function, which is no longer used in
   favour of `addComposerUploadPreProcessor`. The former was used to add preprocessors
   for client side uploads via jQuery file uploader (described at
@@ -29,6 +41,7 @@ jQuery fileupload, which will eventually be removed altogether as a broader effo
   to remove jQuery from the codebase.
 
 ### Changed
+
 - Changes `addComposerUploadHandler`'s behaviour. Instead of being only usable
   for single files at a time, now multiple files are sent to the upload handler
   at once. These multiple files are sent based on the groups in which they are