cmjs — Minimal Client-Side CMS

A minimal CMS where articles are Markdown files rendered in the browser. No build step, no database, no server-side code.

How it works

1. The browser traverses articles/ via a server directory index — discovering authors and their article files; nginx JSON autoindex is preferred, with HTML autoindexes supported as a fallback.
2. Sorting, filtering, and publish status all come from the article file's own name (slug~DDMMYYYY~tags.md) — knowable straight from the listing that discovers it, with no further request per article. A .md file's actual content (title, description, image) is only fetched once that article is about to be shown — the current page's cards, a single article, or a search — not for the whole site up front. See "Adding an article" and "Article discovery & caching" below.
3. Clicking an article fetches the Markdown file and renders it with marked.js.
4. Hash-based routing handles navigation — back/forward works without page reloads.
5. Once an article's content has been fetched, it's cached in IndexedDB, keyed by the article file's own path and invalidated by that file's mtime, so repeat visits skip re-fetching unchanged content — see "Article discovery & caching" below.

Features

• Dark mode — automatically follows the OS prefers-color-scheme setting; no toggle needed.
• Client-side search — the search box in the header filters all articles by title, description, author, category, and tags in-memory. Navigates to #search/query so results are bookmarkable; results paginate the same way the article list does.
• Reading time — estimated from the article word count (200 wpm) and shown on list cards and in article headers. Computed automatically; no frontmatter field needed.
• Table of contents — auto-generated from h2/h3 headings and inserted at the top of the article body. Only appears when the article has three or more headings.
• Back link — a "← Back to articles" link above every article, returning to whatever list, filter, or search page (and page number) the reader actually came from rather than always resetting to page 1 of everything.
• Pagination — article list paginates at 20 articles per page; page state is encoded in the hash so browser history works.
• Author, category, and tag filtering — clicking an author name, category badge, or tag pill shows a filtered list. All three support pagination.
• Responsive layout — layout, cards, images, and pagination all adapt to narrow screens (breakpoint at 640 px).
• Keyboard navigation — all interactive elements have visible :focus-visible outlines for keyboard users.
• Author profiles — a profile card with bio and social links is shown at the top of each author's article list. Created by adding articles/{author}/{author}.md.
• Offline-friendly caching — discovered articles are cached in IndexedDB, so repeat visits skip re-fetching content that hasn't changed.
• Translatable UI — every UI string is looked up from a locale JSON file (English, Czech, and Slovak ship by default); adding a language needs no code changes.

Project structure

This whole repo is cmjs — clone it as-is into an existing site (or copy css/, js/, strings/, templates/, and your own articles/ into one) and embed it into a page there; see "Embedding in an existing page" below. demo/ is a standalone demo/preview page, kept separate from the library — not something an embedding page needs to bring along.

├── README.md
├── demo/                   # Standalone demo/preview page — not needed to embed cmjs elsewhere
│   ├── index.html          # Single-page shell
│   └── css/
│       ├── reset.css       # CSS variables, dark mode, box-sizing reset, focus styles
│       ├── header.css      # Site header, title link, search form
│       └── layout.css      # Main content wrapper, state messages, responsive
├── css/
│   └── components/         # Component styles — needed by any embedding page
│       ├── card.css            # Article list cards and filter heading
│       ├── article.css         # Single article view, back link, hero image
│       ├── content.css         # Rendered markdown styles (.content *)
│       ├── pagination.css      # Prev/next page navigation
│       ├── toc.css             # Auto-generated table of contents
│       └── author-profile.css  # Author profile card (avatar, bio, social links)
├── js/
│   ├── config-default.js  # Shipped defaults for BASE_URL, MARKED_URL, ARTICLES_URL
│   ├── config.js       # Optional local overrides — gitignored; see "Local configuration" below
│   ├── frontmatter.js  # parseFrontmatter() — pure YAML-front parser
│   ├── templates.js    # loadTemplates(), templates cache
│   ├── discovery.js    # discoverArticles(), fetchJson(), article cache
│   ├── cache.js        # IndexedDB cache for discovered articles, keyed by article file path
│   ├── concurrency.js  # mapWithConcurrency() — caps simultaneous per-article fetches
│   ├── i18n.js         # t(), loadStrings(), getLocale() — UI string lookup
│   ├── views.js        # loadArticleList, loadArticle, loadAuthorView, loadCategoryView, loadSearch
│   └── router.js       # Hash router and app entry point
├── vendor/
│   └── marked.min.js   # marked.js (local copy, loaded as a global) — the only 3rd-party code
├── strings/
│   ├── en.json         # UI strings (default/fallback locale) — see "Translations" below
│   ├── cs.json         # Czech translation
│   └── sk.json         # Slovak translation
├── templates/
│   ├── card.html            # Article list card layout
│   ├── article.html         # Full article view layout
│   └── author-profile.html  # Author profile card layout
└── articles/
    └── author/                              # One directory per author
        ├── author.md                        # Author profile (optional)
        ├── media/                           # Shared images for this author — see "Adding an article"
        │   ├── avatar.jpg                    # Referenced by author.md's `avatar:` field
        │   └── cover.jpg                     # Referenced by one or more articles' `image:` field
        └── slug~DDMMYYYY~tag1+tag2.md         # One file per article — see "Adding an article"

Local configuration

js/config-default.js holds the shipped defaults (BASE_URL, MARKED_URL, ARTICLES_URL) and is tracked in git; every other module imports from it. It also loads an optional js/config.js — gitignored, not part of cmjs's own git history — to override any of them. Nothing needs to be created before first use: if js/config.js doesn't exist, the shipped defaults apply as-is.

The split exists for using cmjs as a git submodule (or otherwise pulling in a newer version some other way): since config.js is gitignored, updating cmjs never touches it, so any override you've made survives. Only config-default.js gets updated.

To override a setting, create js/config.js and export just the constant(s) you want to change — anything you don't export falls back to config-default.js. For example, to move where articles live (see "Pointing articles/ somewhere else" below for the matching nginx-side change this needs):

export const ARTICLES_URL = new URL('/blog-content/articles/', location.origin).href;

Adding an article

An article is a single Markdown file placed directly in its author's directory. Its file name is where its publish date, tags, category, and draft status all live — not in separate files, and not in frontmatter. The format is:

<slug>~<DDMMYYYY>~<tag1>+<tag2>+….md

• <slug> — the stable identifier used in the article's URL (#post/author/slug). Treat this as permanent: retagging or correcting the date later just means renaming the file (see below), but changing the slug changes the article's URL.
• <DDMMYYYY> — the publish date, 8 digits, no separators (e.g. 16062026 for 16 June 2026).
• <tag1>+<tag2>+… — zero or more tag ids, joined with +. A tag id matching year-YYYY is treated as the article's "year"/category, shown as a badge linking to #category/year-YYYY; every other tag id is a normal topic tag, shown as a pill linking to #tag/tag-id. Omit this whole segment (and its leading ~) if the article has no tags.

The separator is ~ (tilde), not a hyphen — deliberately, since a slug is expected to be plain kebab-case (single hyphens only) and ~ isn't something you'd type by accident while writing one, unlike an extra -.

A leading underscore on the whole file name — _<slug>~....md — marks the article as a draft: it's excluded from the list, search, and pagination, but still reachable directly by URL. Remove the underscore to publish it.

Images (a cover photo, inline pictures) live in a media/ folder shared by all of that author's articles, not next to each individual article file — so the same picture can be reused across several articles without keeping a duplicate copy per article. Reference one from frontmatter or markdown with a path relative to the author directory, e.g. image: media/photo.jpg.

Steps:

1. Create the author directory if it doesn't exist: articles/author/
2. Create the Markdown file directly inside it, using the naming convention above, e.g. articles/author/my-article~16062026~guides+year-2026.md
3. Optionally add a cover image to that author's shared articles/author/media/ folder (creating it if needed), and reference it from frontmatter with image: media/photo.jpg.
4. Add a frontmatter block at the top of the Markdown file
5. Write your content — it will appear in the list automatically

To change an article's date, tags, or draft status later, rename its file — its content doesn't need to change. author is derived from the containing directory — no frontmatter field needed for it either. Treat the directory name as case-sensitive and exact: it's matched exactly (not case-insensitively) against #author/... URLs and author-profile lookups, so avoid two author directories that differ only in case. Because every one of these is encoded in the file name, discovering an article's metadata never requires fetching anything beyond the directory listing that already reveals it — no further per-article request at all, which is what makes the "Article discovery & caching" section below possible.

A note on trust: article and author-bio Markdown is rendered directly via marked.js with no HTML-sanitization pass — anyone who can write a .md file here can include raw HTML, including <script> tags. Only let people you trust add or edit content.

Frontmatter format

---
title: My Article Title
description: A short summary shown in the article list.
---

Your markdown content here...

Field	Required	Notes
title	yes	Shown in the list and article header
description	no	Short summary shown under the title in the list
image	no	Path to an image in the author's shared media/ folder (e.g. media/photo.jpg); shown as card thumbnail and article hero

Reading time is computed automatically from the article word count — no frontmatter field needed. date, tags, and draft frontmatter fields, if present, are ignored — superseded by the directory name described above.

Author profiles

To add a profile for an author, create a file named {author}.md directly inside the author's directory:

articles/bob/bob.md

The profile appears as a card above the article list when a visitor filters by that author. It is optional — authors without a profile file work normally.

Profile frontmatter

---
title: Bob Johnson
avatar: bob-avatar.jpg
github: https://github.com/bob
twitter: https://twitter.com/bob
linkedin: https://linkedin.com/in/bob
mastodon: https://mastodon.social/@bob
website: https://bob.example.com
---

Short bio rendered as markdown.

Field	Notes
title	Display name shown in the profile card. Falls back to the author directory name.
avatar	Path to an image, relative to the author directory — e.g. media/avatar.jpg if kept in the shared media folder alongside article images, or a bare filename if kept directly beside {author}.md. Displayed as a circular thumbnail.
github / twitter / linkedin / mastodon / website	Any subset of these renders as pill links below the bio.

The body text below the frontmatter is rendered as markdown and shown as the bio.

Routing

URL hash	View
(empty)	All articles, page 1
#page/2	All articles, page 2
#search/linux	Search results for "linux", page 1
#search/linux/page/2	Same, page 2
#author/alice	All articles by alice, page 1
#author/alice/page/2	All articles by alice, page 2
#category/year-2026	All articles carrying the "year-2026" year tag, page 1
#category/year-2026/page/2	Same, page 2
#tag/guides	All articles tagged "guides", page 1
#tag/guides/page/2	Same, page 2
#post/alice/my-article	Single article at articles/alice/my-article~DDMMYYYY~tags.md

Author names and category tags on each card and article are clickable links to their respective filter views. A search box in the header navigates to #search/query.

Customising the layout

The HTML structure for the article list card, the full article view, and the author profile card live in templates/:

• templates/card.html — the card shown in the article list
• templates/article.html — the full article view (header, hero image, content)
• templates/author-profile.html — the profile card (avatar, bio, social links)

Edit these files directly to change layout — no JS changes needed. Elements are identified by data-field attributes, which is how the JS modules find and populate them. Keep existing data-field values when rearranging; add new ones if you add new fields.

Translations

Every UI string the JS renders (loading/error states, pagination, filter labels, the table of contents heading, etc.) is looked up through t(key, params) in js/i18n.js rather than hardcoded — strings/en.json is the default/fallback string table.

Available locales: en (default), cs (Czech), sk (Slovak).

To add another translation:

1. Set <html lang="xx"> on the embedding page (or demo/index.html for this repo's own demo) to the target language code (e.g. cs).
2. Add strings/xx.json with the same keys as en.json (copy it as a starting point) — you only need to include the keys you're translating; anything missing quietly falls back to English rather than breaking.
3. {placeholder} tokens in a string (e.g. "{page} of {totalPages}") are substituted at render time — keep them in your translated string, in whatever order/position reads naturally in that language.

The resolved locale also drives date formatting (Intl.DateTimeFormat), search matching, and tag-label sorting (localeCompare), via getLocale() in the same module — so a translation file doesn't just relabel text, it affects how dates and sorting behave too.

Site-specific branding that lives in the embedding page itself (the page <title>, the header search placeholder, the sidebar section headings) is plain static HTML, not JS-templated — translate it by editing that page directly (demo/index.html for this repo's own demo).

Embedding in an existing page

To add cmjs to any HTML page, three things are needed: the CSS, the two mount-point <div>s, and the script.

1. CSS — in <head>

<!-- Site-level styles (or replace with your own) -->
<link rel="stylesheet" href="demo/css/reset.css">
<link rel="stylesheet" href="demo/css/header.css">
<link rel="stylesheet" href="demo/css/layout.css">

<!-- Component styles -->
<link rel="stylesheet" href="css/components/card.css">
<link rel="stylesheet" href="css/components/article.css">
<link rel="stylesheet" href="css/components/content.css">
<link rel="stylesheet" href="css/components/pagination.css">
<link rel="stylesheet" href="css/components/toc.css">
<link rel="stylesheet" href="css/components/author-profile.css">

The site-level CSS files (reset.css, header.css, layout.css) are optional — they style the shell around the CMS. If your page already has a layout and reset, you can skip them and only load the component stylesheets. Note that reset.css also defines the CSS custom properties (colours, radius) used throughout — if you skip it, define the variables yourself. author-profile.css is only needed if any of your authors have a profile file (see "Author profiles" above) — safe to skip otherwise.

2. Mount points — in <body>

<div id="list-view"></div>
<div id="article-view" hidden></div>

Place these wherever you want the CMS to appear. The router toggles hidden between them on navigation. A search box and tag/year filter lists are optional and can go anywhere else in the page — see "Search, article list, and tag list as independent pieces" below. Unlike those, #list-view/#article-view are both required — router.js checks for them at startup and shows a clear error (scoped to whichever of the two is present, or the whole page if neither is) instead of silently failing if one is missing.

3. Script — before </body>

<script type="module" src="js/router.js"></script>

router.js is the only script tag needed. It loads marked.min.js automatically at startup (path configured in js/config.js).

Subdirectory pages: If the embedding page lives in a subdirectory (e.g. /blog/index.html) and cmjs isn't installed at the site root, a plain relative path like css/... will resolve against the page's directory, not wherever cmjs actually lives. Use a path (root-relative or otherwise) that correctly points at wherever you placed it, e.g. if cmjs lives at /cmjs/ on your site:

<link rel="stylesheet" href="/cmjs/css/components/card.css">
<script type="module" src="/cmjs/js/router.js"></script>

All internal fetches (articles, templates, marked.js) resolve relative to the module files via import.meta.url and work automatically — only the HTML tags need a path pointing at the right place.

Search, article list, and tag list as independent pieces

The mount points above don't have to sit next to each other, or even all be present — each is a plain element the router looks up by id, wherever it happens to be in your page. This lets you scatter search, the article list, and the tag list across a custom layout (search box in the site header, tag list in a sidebar, articles in the main column) instead of stacking them the way the demo does.

• Article list + single article — #list-view / #article-view. These two are the only required pair; the router toggles hidden between them and always needs both present somewhere on the page. This pair is also where search results render — there's no separate results container, so any page using the search box below still needs #list-view on it somewhere to actually show what was searched for.
• Search box — #search-form / #search-input. Fully optional and independent; place it anywhere (e.g. a site-wide header, not necessarily near the list). Submitting it navigates to #search/query; matches render into #list-view.

  <form id="search-form" role="search">
      <input type="search" id="search-input" placeholder="Search articles…" autocomplete="off">
  </form>
  

• Tag list — #tag-filters. Optional; put a container (a <nav> works well) anywhere, e.g. a sidebar. It's automatically filled in with one link per tag in use (alphabetical, with an article count) every time a list view renders — no manual updates needed. Clicking a tag navigates to #tag/tag-id, rendering the filtered list into #list-view.

  <nav id="tag-filters" aria-label="Filter by tag"></nav>
  

• Year list — #year-filters (optional, not used by this repo's own demo but supported the same way): a container that gets filled in with one link per year 2026 down to 2009 that has at least one article, linking to #category/year-YYYY. Can appear alongside #tag-filters or on its own.

  <nav id="year-filters" aria-label="Filter by year"></nav>
  

Both filter lists are populated by the same function on every list render, so whichever of #tag-filters/#year-filters is present just gets filled in — omit either one (or both) and nothing breaks, the article list and search still work standalone.

Minimal example

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>My Site</title>
    <link rel="stylesheet" href="css/components/card.css">
    <link rel="stylesheet" href="css/components/article.css">
    <link rel="stylesheet" href="css/components/content.css">
    <link rel="stylesheet" href="css/components/pagination.css">
    <link rel="stylesheet" href="css/components/toc.css">
</head>
<body>
    <div id="list-view"></div>
    <div id="article-view" hidden></div>

    <script type="module" src="js/router.js"></script>
</body>
</html>

nginx configuration

Point nginx root at the repo root. The autoindex directive applies recursively to all subdirectories under /articles/.

server {
    listen 80;
    server_name example.com;
    root /var/www/cmjs;

    # Serve the demo page
    location /demo/ {
        try_files $uri $uri/ /demo/index.html;
    }

    # Enable JSON directory listing for article discovery (applies to all subdirs)
    location /articles/ {
        autoindex on;
        autoindex_format json;
        autoindex_localtime off;  # keep mtimes in GMT — the crawler's cache relies on consistent, unambiguous timestamps
    }
}

Note: autoindex_format json requires nginx 1.7.9+. Check with nginx -v. If autoindex_format json is ever lost (config drift, an older nginx), the crawler falls back to parsing nginx's default HTML directory listing instead of breaking outright.

Pointing articles/ somewhere else

By default the crawler looks for articles at articles/ next to the rest of cmjs (ARTICLES_URL, computed as a sibling of the js/ folder). Articles don't have to live there — override ARTICLES_URL in your local js/config.js (see "Local configuration" above) to point anywhere under the same origin (or a different one, CORS permitting).

Whatever it resolves to needs its own matching location block enabling the JSON (or HTML) autoindex — it doesn't have to be named articles/ or nested under wherever cmjs itself lives:

location /blog-content/articles/ {
    autoindex on;
    autoindex_format json;
    autoindex_localtime off;
}

Compression

Markdown and directory-listing JSON are both plain text, so gzip shrinks them well — and since the browser decompresses transparently, this needs no changes on the cmjs side. nginx doesn't know .md is text by default (it falls back to application/octet-stream, which gzip_types won't match), so map it explicitly and enable gzip for both content types:

# in http {} or a shared mime block
types {
    text/markdown md;
}

# in http {} or the server block above
gzip on;
gzip_types text/markdown text/plain application/json;  # json covers the autoindex_format listings
gzip_min_length 256;
gzip_vary on;

Pre-compressing with gzip_static is possible but needs a .md.gz alongside every article, which is a build step this project deliberately has none of — plain runtime gzip on is the better fit here. Brotli usually compresses text better still, but needs the separate ngx_brotli module, not built into stock nginx — only worth it if you're already building custom nginx modules.

Article discovery & caching

Discovery happens in two phases. Indexing crawls articles/ client-side to build a lightweight "stub" for every article — the author directories, then each author's own directory listing (their article files, bio file, and shared media/ folder together) along with each file's mtime. Non-article entries (the author's own {author}.md, the media/ folder) are simply filtered out of that same listing. That's it: because an article file's name already encodes its slug, date, tags, and draft status (see "Adding an article" above), that single listing is enough to sort, filter, paginate, and populate the sidebar's tag/year counts, without any further request per article and without ever fetching an article's actual Markdown. Hydration is the separate, deferred step that fetches a specific article's content (title, description, cover image, reading time) — it only ever runs for articles about to be rendered: the current page's cards (hydrateArticles() in js/discovery.js), a single visited article, or (since full-text search needs real content) as many search results as the page being viewed actually needs. A large site's list is therefore fast to show regardless of how many articles it has — indexing costs one request per author, full stop, and only ~20 articles' worth of content is ever fetched per page view.

• Cache — hydrated articles are cached per article file in IndexedDB (js/cache.js), keyed by the file's own path and invalidated by comparing its live mtime against the cached one — once any visit renders an article, every later visit skips its content fetch too, until the file is renamed (a rename changes the cache key, so a retagged/redated article is treated as new — see "Adding an article" above) or its own mtime changes. Indexing reads the entire cache once up front (getAllCacheEntries(), kicked off in parallel with the author/directory-listing requests) so a warm cache doesn't cost an IndexedDB read per article. If IndexedDB is unavailable (private browsing, disabled storage), discovery transparently falls back to fetching everything live on every visit.
• Cache schema version — the cached records store the full derived article shape, not raw content, so a code change to how articles are derived (in js/discovery.js) can make old cached entries stale in structure, not just content — and a file's mtime won't catch that. Bump CACHE_SCHEMA_VERSION in js/cache.js whenever that shape changes; it's baked into the IndexedDB database name, so a bump invalidates every cached entry on the next deploy.
• Concurrency — MAX_CONCURRENT_REQUESTS in js/discovery.js (default 10) caps how many hydration (content) fetches run at once — the only per-article requests left, since indexing no longer needs one; raise it for a fast/local nginx, lower it for a slow or shared/ production instance.
• Prefetching — once the current page has fully rendered, the next page's articles are hydrated in the background (fire-and-forget), so clicking "next" is usually an instant cache hit rather than a fresh round-trip.
• Paused/resumable search — search needs real text (title, description), unlike the list view, so it hydrates articles rather than just reading stubs — but only as many as the page being viewed needs, in the same newest-first order as everything else (loadSearch() in js/views.js). It scans stubs in small batches, stops as soon as it's found enough matches to fill the current page (plus one, just to know whether a next page exists), and resumes exactly where it left off — no re-checking — if the user pages further into the same query. Paging back needs no scanning at all, since matches only ever accumulate. This keeps a search on a large site to a handful of requests instead of hydrating the entire article set up front. The page count is exact once the whole set's been scanned, and a lower bound (at least one more page) until then.
• Crawl health — if the root author-listing fetch fails outright, if every individual author's own directory listing fails, or if very few of the known candidate files parsed successfully (a malformed file name, or a total breakage like the wrong origin or CORS misconfigured), a small warning banner is shown above the article list instead of silently rendering an empty page (see getCrawlStats() / renderCrawlHealthWarning() in js/discovery.js / js/views.js).
• Design rationale — the original crawler design (wave-based crawling with a per-article listing fetch, recency prioritisation, HTML-autoindex fallback, long-term "deploy and forget" constraints) is documented in .claude/nginx-sitemap-crawler-plan.md, which ships alongside the code. The per-article listing fetch it describes no longer exists (metadata moved into the file name instead, and articles no longer live in a directory of their own), but the rest of that reasoning — the caching model, the longevity constraints, the HTML fallback — still applies.

Running locally

Using nginx locally (example for Linux):

# Symlink or copy the repo to your nginx webroot, then reload:
sudo nginx -s reload

Then open /demo/ in a browser to preview.

Python's http.server returns HTML directory listings, not JSON, so article discovery won't work with it. Use nginx.