resolves #2498 configure asciimath block to render as displaymath (PR #…

…3192)

- use an AsciiMath postfilter hook to change the display property to block

CHANGELOG.adoc

@@ -15,6 +15,10 @@ For a detailed view of what has changed, refer to the {uri-repo}/commits/master[
 
 == Unreleased
 
+Bug Fixes::
+
+  * customize MathJax (using a postfilter hook) to apply displaymath formatting to AsciiMath block (#2498)
+
 Build / Infrastructure::
 
   * bundle .yardopts in RubyGem (#3193)

lib/asciidoctor/converter/html5.rb

@@ -264,6 +264,14 @@ def convert_document node
   },
   TeX: {#{eqnums_opt}}
 })
+MathJax.Hub.Register.StartupHook("AsciiMath Jax Ready", function () {
+  MathJax.InputJax.AsciiMath.postfilterHooks.Add(function (data, node) {
+    if ((node = data.script.parentNode) && (node = node.parentNode) && node.classList.contains('stemblock')) {
+      data.math.root.display = "block"
+    }
+    return data
+  })
+})
 </script>
 <script src="#{cdn_base_url}/mathjax/#{MATHJAX_VERSION}/MathJax.js?config=TeX-MML-AM_HTMLorMML"></script>)
     end