only copy mermaid dist if needed in docs build

also keep mermaid dist in its own static folder

sphinx_immaterial/mermaid_diagrams.py

@@ -1,9 +1,15 @@
 """A custom directive that allows using mermaid diagrams"""
+from pathlib import Path
+import shutil
 from typing import List
 from docutils import nodes
 from docutils.parsers.rst import directives
 from sphinx.util.docutils import SphinxDirective
 from sphinx.application import Sphinx
+from sphinx.environment import BuildEnvironment
+
+# name of a flag to track if the mermaid dist is needed in the docs build
+_COPY_MERMAID_DIST_ENV_KEY = "sphinx_immaterial_copy_mermaid_dist"
 
 
 class mermaid_node(nodes.General, nodes.Element):
@@ -34,6 +40,7 @@ def run(self) -> List[nodes.Node]:
             self.add_name(diagram_div)
         diagram_div += diagram
         self.set_source_info(diagram_div)
+        setattr(self.env, _COPY_MERMAID_DIST_ENV_KEY, True)
         return [diagram_div]
 
 
@@ -54,13 +61,31 @@ def depart_mermaid_node_latex(self, node: mermaid_node):
     self.body.append("\n\\end{sphinxVerbatim}\n")
 
 
+def on_builder_init(app: Sphinx):
+    """Init the copy-mermaid-dist flag to False"""
+    setattr(app.env, _COPY_MERMAID_DIST_ENV_KEY, False)
+
+
+def copy_mermaid_dist(app: Sphinx, env: BuildEnvironment):
+    if app.builder.name not in ("html", "dirhtml"):
+        return  # mermaid src is only used in HTML output
+    if getattr(app.env, _COPY_MERMAID_DIST_ENV_KEY, False) is True:
+        # copy the mermaid dist file (if not already done)
+        dst = Path(app.outdir, "_static", "mermaid")
+        if dst.exists():
+            return
+        shutil.copytree(str(Path(__file__).parent / "static" / "mermaid"), dst)
+
+
 def setup(app: Sphinx):
     app.add_directive("md-mermaid", MermaidDirective)
     app.add_node(
         mermaid_node,
         html=(visit_mermaid_node_html, depart_mermaid_node_html),
         latex=(visit_mermaid_node_latex, depart_mermaid_node_latex),
     )
+    app.connect("builder-inited", on_builder_init)
+    app.connect("env-check-consistency", copy_mermaid_dist)
     return {
         "parallel_read_safe": True,
         "parallel_write_safe": True,

src/assets/javascripts/components/content/code/mermaid/index.ts

@@ -75,7 +75,7 @@ const config = configuration()
  */
 function fetchScripts(): Observable<void> {
   return typeof mermaid === "undefined" || mermaid instanceof Element
-    ? watchScript(`${config.base}_static/mermaid.min.js`) // sphinx-immaterial uses cached dist
+    ? watchScript(`${config.base}_static/mermaid/mermaid.min.js`) // sphinx-immaterial uses cached dist
     : of(undefined)
 }
 

tools/build/index.ts

@@ -132,7 +132,7 @@ const assets$ = concat(
   ...["mermaid.min.js*"]
     .map(pattern => copyAll(pattern, {
       from: "node_modules/mermaid/dist",
-      to: `${base}/static`
+      to: `${base}/static/mermaid`
     })),
 
   /* Copy mathjax dist */