doc: Added yaml-metadata doc into hedgedoc frontend

docs/content/references/yaml-metadata.md

@@ -0,0 +1,176 @@
+# Supported YAML metadata
+
+With a YAML frontmatter you can change certain metadata and aspects of your note.
+
+First you need to insert syntax like this at the **start** of the note:
+```yaml
+---
+YAML metas
+---
+```
+
+Replace the "YAML metas" in this section with any YAML options as below.
+You can also refer to this note's source code.
+
+## title
+
+This option will set the note title which prior than content title.
+
+> default: not set
+
+**Example**
+```yml
+title: meta title
+```
+
+## description
+
+This option will set the note description as a `<meta name="description">` tag. This only affects the [Publish](../features#Share-Notes) function.
+
+> default: not set
+
+**Example**
+```yml
+description: meta description
+```
+
+## tags
+
+This option will set the tags which prior than content tags.
+
+> default: not set
+
+**Example**
+```yml
+tags: features, cool, updated
+```
+
+## robots
+
+This option will give below meta in the note head meta:
+```xml
+<meta name="robots" content="your_meta">
+```
+So you can prevent any search engine index your note by set `noindex, nofollow`.
+
+> default: not set
+
+**Example**
+```yml
+robots: noindex, nofollow
+```
+
+## lang
+
+This option will set the language of the note.
+Setting the language helps the browser to apply rules such as typography correctly.
+You can find your the language code in ISO 639-1 standard:
+<https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes>
+
+> default: not set (which will be en)
+
+**Example**
+```yml
+lang: ja-jp
+```
+
+## dir
+
+This option specifies the direction of the text in this note.
+You can only use whether `rtl` or `ltr`.
+Look more at here:
+<http://www.w3.org/International/questions/qa-html-dir>
+
+> default: not set (which will be ltr)
+
+**Example**
+```yml
+dir: rtl
+```
+
+## breaks
+
+This option means the hardbreaks in the note will be parsed or be ignore.
+The original markdown syntax breaks only if you put space twice, but HedgeDoc choose to breaks every time you enter a break.
+You can only use whether `true` or `false`.
+
+> default: not set (which will be true)
+
+**Example**
+```yml
+breaks: false
+```
+
+## GA
+
+This option allows you to enable Google Analytics with your ID.
+
+> default: not set (which won't enable)
+
+**Example**
+```yml
+GA: UA-12345667-8
+```
+
+## disqus
+
+This option allows you to enable Disqus with your shortname.
+
+> default: not set (which won't enable)
+
+**Example**
+```yml
+disqus: hedgedoc
+```
+
+## type
+
+This option allows you to switch the document view to the slide preview, to simplify live editing of presentations.
+
+> default: not set
+
+**Example:**
+```yml
+type: slide
+```
+
+## slideOptions
+
+This option allows you to provide custom options to slide mode.
+
+Slide mode is achieved using [Reveal](https://revealjs.com/), an HTML presentation framework.
+The current stable version of HedgeDoc uses Reveal 3.
+
+See the document below for more details on the available slide options:
+<https://github.com/hakimel/reveal.js/blob/3.9.2/README.md#configuration>
+
+You could also set slide theme which named in below css files:
+<https://github.com/hakimel/reveal.js/tree/master/css/theme>
+
+**Notice: always use two spaces as indention in YAML metadata!**
+
+> default: not set (which use default slide options)
+
+**Example**
+```yml
+slideOptions:
+  transition: fade
+  theme: white
+```
+
+## opengraph
+
+This option allows you to override the default generated opengraph metadata.
+See the [OpenGraph protocol documentation](https://ogp.me) for more information.
+
+**Notice: always use two spaces as indention in YAML metadata!**
+
+> default: not set (uses auto-generated metadata)
+
+**Example**
+```yml
+opengraph:
+  title: Special title for OpenGraph protocol
+  image: https://dummyimage.com/600x600/000/fff
+  image:type: image/png
+```

docs/mkdocs.yml

@@ -39,6 +39,7 @@ nav:
       - 'HedgeDoc Flavored Markdown': references/hfm.md
       - 'Slide Options': references/slide-options.md
       - 'URL Scheme': references/url-scheme.md
+      - 'YAML Metadata': references/yaml-metadata.md
   - Developer:
       - 'Getting Started': dev/getting-started.md
       - API: dev/api.md