chore: import upstream snapshot with attribution

tools/challenge-parser/parser/plugins/add-interactive-elements.js

@@ -0,0 +1,73 @@
+const { root } = require('mdast-builder');
+const find = require('unist-util-find');
+const { isEmpty } = require('lodash');
+
+const { getFilenames } = require('./utils/get-file-visitor');
+const { getSection, isMarker } = require('./utils/get-section');
+const mdastToHTML = require('./utils/mdast-to-html');
+
+function plugin() {
+  return transformer;
+
+  function transformer(tree, file) {
+    const interactiveNodes = getSection(tree, `--interactive--`, 1);
+    const subSection = find(root(interactiveNodes), isMarker);
+    if (subSection) {
+      throw Error(
+        `The --interactive-- section should not have any subsections. Found subsection ${subSection.children[0].value}`
+      );
+    }
+
+    if (!isEmpty(interactiveNodes)) {
+      const nodules =
+        interactiveNodes.map(node => {
+          if (
+            node.type === 'containerDirective' &&
+            node.name === 'interactive_editor'
+          ) {
+            return {
+              type: 'interactiveEditor',
+              files: getFiles(node.children)
+            };
+          } else {
+            const paragraph = mdastToHTML([node]);
+            return {
+              type: 'paragraph',
+              contents: paragraph
+            };
+          }
+        }) ?? [];
+
+      file.data.nodules = nodules;
+    }
+  }
+}
+
+function getFiles(filesNodes) {
+  const invalidNode = filesNodes.find(node => node.type !== 'code');
+  if (invalidNode) {
+    throw Error('The :::interactive_editor should only contain code blocks.');
+  }
+
+  // TODO: refactor into two steps, 1) count languages, 2) map to files
+  const counts = {};
+
+  return filesNodes.map(node => {
+    counts[node.lang] = counts[node.lang] ? counts[node.lang] + 1 : 1;
+
+    const contentsHtml = mdastToHTML([node]);
+
+    const out = {
+      contents: node.value,
+      ext: node.lang,
+      name:
+        getFilenames(node.lang) +
+        (counts[node.lang] ? `-${counts[node.lang]}` : ''),
+      contentsHtml
+    };
+
+    return out;
+  });
+}
+
+module.exports = plugin;