feat: linked articles in header

eleventy.config.js

@@ -3,6 +3,7 @@ import markdownIt from "markdown-it";
 import markdownItAnchor from "markdown-it-anchor";
 import { filters } from "./src/_filters/index.js";
 import { postComparator, isPostPublic } from "./src/_utils/sort-posts.js";
+import { validateLinkedArticles } from "./src/_utils/linked-articles.js";
 
 export default function (eleventyConfig) {
   // Build ignored local post fixtures without making them Git-tracked.
@@ -44,8 +45,10 @@ export default function (eleventyConfig) {
   // 5. Custom Collections
   // Pinned / featured prioritized, chronological blog posts collection (excludes drafts and hidden posts)
   eleventyConfig.addCollection("posts", (collectionApi) => {
-    return collectionApi
-      .getFilteredByGlob("src/posts/*.md")
+    const allPosts = collectionApi.getFilteredByGlob("src/posts/*.md");
+    validateLinkedArticles(allPosts);
+
+    return allPosts
       .filter((post) => isPostPublic(post))
       .sort(postComparator);
   });

src/_filters/index.js

@@ -1,5 +1,6 @@
 import { DateTime } from "luxon";
 import markdownIt from "markdown-it";
+import { resolveLinkedArticles } from "../_utils/linked-articles.js";
 
 /**
  * Custom Eleventy Filters for River Rooks Blog
@@ -108,7 +109,8 @@ export const filters = {
   readingTime,
   extractHeadings,
   extractTerminalPreview,
-  removeTerminalPreview
+  removeTerminalPreview,
+  resolveLinkedArticles
 };
 
 export default filters;

src/_includes/layouts/post.njk

@@ -31,6 +31,17 @@
     <!-- Article Telemetry Tile -->
     <div class="sidebar-tile">
       <div class="sidebar-heading">DISPATCH TELEMETRY</div>
+      {% set linkedPosts = collections.posts | resolveLinkedArticles(linkedArticles) %}
+      {% if linkedPosts.length > 0 %}
+        <section aria-labelledby="other-articles-heading">
+          <div id="other-articles-heading" class="sidebar-heading">OTHER ARTICLES</div>
+          <nav class="toc-nav" aria-label="Other Articles">
+            {% for linkedPost in linkedPosts %}
+              <a href="{{ linkedPost.url }}" class="toc-link">{{ linkedPost.data.title }}</a>
+            {% endfor %}
+          </nav>
+        </section>
+      {% endif %}
       <div class="sidebar-stats-box" style="padding: 0; background: transparent; border: none;">
         {% if hidden and hidden != "false" and hidden != "0" and hidden != "no" %}
           <div class="stat-row">

src/_utils/linked-articles.js

@@ -0,0 +1,48 @@
+export const validateLinkedArticles = (posts) => {
+  const titles = new Set(posts.map((post) => post.data.title));
+
+  for (const post of posts) {
+    const { linkedArticles } = post.data;
+
+    if (linkedArticles === undefined) continue;
+
+    if (!Array.isArray(linkedArticles)) {
+      throw new Error(
+        `Post '${post.inputPath}' must define 'linkedArticles' as a YAML list of article titles`
+      );
+    }
+
+    const linkedTitleSet = new Set();
+    for (const title of linkedArticles) {
+      if (typeof title !== "string" || title.trim() === "") {
+        throw new Error(
+          `Post '${post.inputPath}' must define 'linkedArticles' with non-empty article titles`
+        );
+      }
+
+      if (title === post.data.title) {
+        throw new Error(`Post '${post.inputPath}' cannot link to itself`);
+      }
+
+      if (linkedTitleSet.has(title)) {
+        throw new Error(
+          `Post '${post.inputPath}' cannot contain duplicate article titles in 'linkedArticles'`
+        );
+      }
+      linkedTitleSet.add(title);
+
+      if (!titles.has(title)) {
+        throw new Error(
+          `Post '${post.inputPath}' links to unknown article '${title}'`
+        );
+      }
+    }
+  }
+};
+
+export const resolveLinkedArticles = (posts, titles) => {
+  if (!Array.isArray(posts) || !Array.isArray(titles)) return [];
+
+  const postsByTitle = new Map(posts.map((post) => [post.data.title, post]));
+  return titles.map((title) => postsByTitle.get(title)).filter(Boolean);
+};

test/linked-articles.test.js

@@ -0,0 +1,153 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import path from "node:path";
+import { resolveLinkedArticles, validateLinkedArticles } from "../src/_utils/linked-articles.js";
+import { filters } from "../src/_filters/index.js";
+import configureEleventy from "../eleventy.config.js";
+
+test("Linked articles: accepts an article's list when every name identifies another post", () => {
+  assert.doesNotThrow(() => {
+    validateLinkedArticles([
+      {
+        inputPath: "src/posts/2026-10-06-terminal-preview-demo.md",
+        data: {
+          title: "Terminal Preview Demo",
+          linkedArticles: ["Markdown Preview Demo"]
+        }
+      },
+      {
+        inputPath: "src/posts/2026-10-05-markdown-preview-demo.md",
+        data: { title: "Markdown Preview Demo" }
+      }
+    ]);
+  });
+});
+
+test("Linked articles: rejects a non-list frontmatter value", () => {
+  assert.throws(
+    () => {
+      validateLinkedArticles([
+        {
+          inputPath: "src/posts/2026-10-06-terminal-preview-demo.md",
+          data: {
+            title: "Terminal Preview Demo",
+            linkedArticles: "Markdown Preview Demo"
+          }
+        },
+        {
+          inputPath: "src/posts/2026-10-05-markdown-preview-demo.md",
+          data: { title: "Markdown Preview Demo" }
+        }
+      ]);
+    },
+    /must define 'linkedArticles' as a YAML list/
+  );
+});
+
+test("Linked articles: rejects empty and unknown article names", () => {
+  const posts = [
+    {
+      inputPath: "src/posts/2026-10-06-terminal-preview-demo.md",
+      data: { title: "Terminal Preview Demo", linkedArticles: [""] }
+    },
+    {
+      inputPath: "src/posts/2026-10-05-markdown-preview-demo.md",
+      data: { title: "Markdown Preview Demo" }
+    }
+  ];
+
+  assert.throws(() => validateLinkedArticles(posts), /non-empty article titles/);
+
+  posts[0].data.linkedArticles = ["Missing Dispatch"];
+  assert.throws(() => validateLinkedArticles(posts), /links to unknown article 'Missing Dispatch'/);
+});
+
+test("Linked articles: rejects self-references and duplicate navigation targets", () => {
+  const posts = [
+    {
+      inputPath: "src/posts/2026-10-06-terminal-preview-demo.md",
+      data: {
+        title: "Terminal Preview Demo",
+        linkedArticles: ["Terminal Preview Demo"]
+      }
+    },
+    {
+      inputPath: "src/posts/2026-10-05-markdown-preview-demo.md",
+      data: { title: "Markdown Preview Demo" }
+    }
+  ];
+
+  assert.throws(() => validateLinkedArticles(posts), /cannot link to itself/);
+
+  posts[0].data.linkedArticles = ["Markdown Preview Demo", "Markdown Preview Demo"];
+  assert.throws(() => validateLinkedArticles(posts), /cannot contain duplicate article titles/);
+});
+
+test("Linked articles: the Eleventy posts collection rejects invalid frontmatter", () => {
+  const collections = new Map();
+  configureEleventy({
+    setUseGitIgnore() {},
+    addPassthroughCopy() {},
+    addPlugin() {},
+    setLibrary() {},
+    addFilter() {},
+    addCollection(name, callback) {
+      collections.set(name, callback);
+    },
+    setServerOptions() {}
+  });
+
+  assert.throws(
+    () => {
+      collections.get("posts")({
+        getFilteredByGlob() {
+          return [
+            {
+              inputPath: "src/posts/2026-10-06-terminal-preview-demo.md",
+              data: {
+                title: "Terminal Preview Demo",
+                linkedArticles: ["Missing Dispatch"]
+              }
+            }
+          ];
+        }
+      });
+    },
+    /links to unknown article 'Missing Dispatch'/
+  );
+});
+
+test("Linked articles: resolves named posts in the frontmatter order for navigation", () => {
+  const posts = [
+    {
+      url: "/dispatches/terminal-preview-demo/",
+      data: { title: "Terminal Preview Demo" }
+    },
+    {
+      url: "/dispatches/markdown-preview-demo/",
+      data: { title: "Markdown Preview Demo" }
+    }
+  ];
+
+  assert.deepEqual(
+    resolveLinkedArticles(posts, ["Markdown Preview Demo", "Terminal Preview Demo"]),
+    [posts[1], posts[0]]
+  );
+});
+
+test("Linked articles: exposes navigation resolution to Nunjucks", () => {
+  assert.strictEqual(filters.resolveLinkedArticles, resolveLinkedArticles);
+});
+
+test("Linked articles: post layout renders Other Articles at the top of dispatch telemetry", () => {
+  const postLayout = fs.readFileSync(
+    path.resolve("src/_includes/layouts/post.njk"),
+    "utf-8"
+  );
+
+  assert.match(
+    postLayout,
+    /{% set linkedPosts = collections\.posts \| resolveLinkedArticles\(linkedArticles\) %}[\s\S]*?<div[^>]+class="sidebar-heading">OTHER ARTICLES<\/div>[\s\S]*?<nav[^>]+aria-label="Other Articles">[\s\S]*?href="{{ linkedPost\.url }}"/
+  );
+});