Add section parsing and classification

Author: AaronO

lib/is_exercise.js

@@ -0,0 +1,17 @@
+var _ = require('lodash');
+
+function isExercise(nodes) {
+    var codeType = { type: 'code' };
+
+    // Number of code nodes in section
+    var len = _.filter(nodes, codeType).length;
+
+    return (
+        // Got 3 or 4 code blocks
+        (len === 3 || len === 4) &&
+        // Ensure all nodes are at the end
+        _.all(_.last(nodes, len), codeType)
+    );
+}
+
+module.exports = isExercise;

lib/sections.js

@@ -0,0 +1,38 @@
+var _ = require('lodash');
+
+// Split a page up into sections (lesson, exercises, ...)
+function split(nodes) {
+    var section = [];
+
+    return _(nodes)
+    .reduce(, function(sections, el) {
+        if(el.type === 'hr') {
+            sections.push(section);
+            section = [];
+            section.links = nodes.links || {};
+        } else {
+            section.push(el);
+        }
+
+        return sections;
+    }, [])
+     // Add remaining nodes
+    .concat([section])
+    // Exclude empty sections
+    .filter(_.negate(_.isEmpty))
+    // Spit out JS array
+    .value();
+}
+
+function join(sections) {
+    var nodes = _.reduce(sections, function(nodes, section) {
+        return nodes.concat(section);
+    }, []);
+    nodes.links = (sections[0] && (sections[0].links) || {};
+    return nodes;
+}
+
+module.exports = {
+    split: split,
+    join: split,
+};