Add compact_html render option to suppress newlines in HTML output

Author: gjtorikian

README.md

@@ -181,6 +181,7 @@ Note that there is a distinction in comrak for "parse" options and "render" opti
 | `gfm_quirks`         | Outputs HTML with GFM-style quirks; namely, not nesting `<strong>` inlines.                            | `false` |
 | `prefer_fenced`      | Always output fenced code blocks, even where an indented one could be used.                            | `false` |
 | `tasklist_classes`   | Add CSS classes to the HTML output of the tasklist extension                                           | `false` |
+| `compact_html`       | Suppress newlines in pretty-printed HTML output.                                                       | `false` |
 
 As well, there are several extensions which you can toggle in the same manner:
 

ext/commonmarker/src/options.rs

@@ -53,6 +53,7 @@ const RENDER_IGNORE_EMPTY_LINKS: &str = "ignore_empty_links";
 const RENDER_GFM_QUIRKS: &str = "gfm_quirks";
 const RENDER_PREFER_FENCED: &str = "prefer_fenced";
 const RENDER_TASKLIST_CLASSES: &str = "tasklist_classes";
+const RENDER_COMPACT_HTML: &str = "compact_html";
 
 pub fn iterate_render_options(comrak_options: &mut comrak::options::Render, options_hash: RHash) {
     options_hash
@@ -94,6 +95,9 @@ pub fn iterate_render_options(comrak_options: &mut comrak::options::Render, opti
                 Cow::Borrowed(RENDER_TASKLIST_CLASSES) => {
                     comrak_options.tasklist_classes = TryConvert::try_convert(value)?;
                 }
+                Cow::Borrowed(RENDER_COMPACT_HTML) => {
+                    comrak_options.compact_html = TryConvert::try_convert(value)?;
+                }
                 _ => {}
             }
             Ok(ForEach::Continue)

lib/commonmarker/config.rb

@@ -26,6 +26,7 @@ module Config
         gfm_quirks: false,
         prefer_fenced: false,
         tasklist_classes: false,
+        compact_html: false,
       }.freeze,
       extension: {
         strikethrough: true,

test/rendering_test.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class RenderingTest < Minitest::Test
+  def test_compact_html
+    markdown = "# Hello\n\nWorld\n"
+
+    default_output = Commonmarker.to_html(markdown)
+    compact_output = Commonmarker.to_html(markdown, options: { render: { compact_html: true } })
+
+    assert_operator(compact_output.count("\n"), :<, default_output.count("\n"))
+  end
+end