More progress on parser.

docs/parser/helpers.js

@@ -0,0 +1,17 @@
+
+module.exports.contentAsText = async function(doc, rootLevel) {
+  const { level, next, line, head } = doc
+  const linesAsArray = []
+
+  let contentDepth = -1
+
+  while(await next(rootLevel)) {
+    if (!line()) continue
+    if (contentDepth === -1) contentDepth = level()
+
+    const indent = ''.padStart(level() - contentDepth, ' ')
+    linesAsArray.push(indent + line())
+  }
+
+  return linesAsArray.join('\n')
+}