Language

Comments

# and ### comments, where # is not a comment, and writing # in text.

Single-line comments

# starts a comment that runs to the end of the line. It can follow code:

# the page header
[h1]Welcome[end] # shown on every page

<h1>Welcome</h1>

Multi-line comments

Everything between ### and ### is a comment, on many lines or inside one:

###
  Draft section:
  not ready yet
###
[p]Ready ### and this is hidden ### now[end]

<p>Ready now</p>

Between props

A prop list on several lines can have comments too:

[img =
  src: "logo.svg",   # 64 × 64
  alt: "Logo"
!]

<img src="logo.svg" alt="Logo">

Where # is not a comment

• Inside quotes: [a = href: "/page#top"].
• Inside ${ }$: it's JavaScript, so use // and /* */.
• Inside [style]: it's CSS, so #888 is a color and comments are /* */.
• Inside a block with arcm-raw: true.

${
  // JavaScript comments in ${ }$
  const page = "/page";
}$
[a = href: "/page#top"]Top[end]
[pre = arcm-raw: true]# shown as written[end]
[style]
  /* CSS comments in [style] */
  .note { color: #888; }
[end]

<style>.note{color:#888}</style><a href="/page#top">Top</a>
<pre># shown as written</pre>

Writing # in text

In text, write \#. Try it: remove the backslash and press Run:

[p]Issue \#42 is fixed[end]

Without it, the rest of the line is a comment, and ArcMoon says so:

✗ [p] opened at 1:1 is missing [end]. The "#" on line 1 starts a comment, which hides the rest of that line, including its [end]. For the character itself, write \#

Keeping comments in the HTML

By default, ArcMoon leaves comments out of the HTML. To keep them as HTML comments (<!-- -->), set removeComments to false in arcmoon.config.js:

export default {
  removeComments: false
};

Then arcm build turns every # and ### comment into an HTML comment, in the same place:

# Page header
[h1]Welcome[end] # shown on every page
###
  License: MIT
###
[p]Hello[end]

<!-- Page header-->
<h1>Welcome</h1> <!-- shown on every page-->
<!--
  License: MIT
-->
<p>Hello</p>

• It applies to every page built with that config.
• From JavaScript, pass the same option: new ArcMoon({ src, removeComments: false }).
• Comments in ${ }$ (JavaScript) and [style] (CSS) are never written to the HTML.
• Useful for notes that should ship with the page, like a license.