Merge pull request #472 from GitbookIO/fix/quizzes

Fix/quizzes

1 files changed, 87 insertions, 0 deletions

diff --git a/lib/parse/is_quiz.js b/lib/parse/is_quiz.js
new file mode 100644
index 0000000..3322ff0
--- /dev/null
+++ b/lib/parse/is_quiz.js
@@ -0,0 +1,87 @@
+var _ = require('lodash');
+
+function isQuizNode(node) {
+    return (/^[(\[][ x][)\]]/).test(node.text || node);
+}
+
+function isTableQuestion(nodes) {
+    var block = questionBlock(nodes);
+    return (
+        block.length === 1 &&
+        block[0].type === 'table' &&
+        _.all(block[0].cells[0].slice(1), isQuizNode)
+    );
+}
+
+function isListQuestion(nodes) {
+    var block = questionBlock(nodes);
+    // Counter of when we go in and out of lists
+    var inlist = 0;
+    // Number of lists we found
+    var lists = 0;
+    // Elements found outside a list
+    var outsiders = 0;
+    // Ensure that we have nothing except lists
+    _.each(block, function(node) {
+        if(node.type === 'list_start') {
+            inlist++;
+        } else if(node.type === 'list_end') {
+            inlist--;
+            lists++;
+        } else if(inlist === 0) {
+            // Found non list_start or list_end whilst outside a list
+            outsiders++;
+        }
+    });
+    return lists > 0 && outsiders === 0;
+}
+
+function isQuestion(nodes) {
+    return isListQuestion(nodes) || isTableQuestion(nodes);
+}
+
+// Remove (optional) paragraph header node and blockquote
+function questionBlock(nodes) {
+    return nodes.slice(
+        nodes[0].type === 'paragraph' ? 1 : 0,
+        _.findIndex(nodes, { type: 'blockquote_start' })
+    );
+}
+
+function splitQuestions(nodes) {
+    // Represents nodes in current question
+    var buffer = [];
+    return _.reduce(nodes, function(accu, node) {
+        // Add node to buffer
+        buffer.push(node);
+
+        // Flush buffer once we hit the end of a question
+        if(node.type === 'blockquote_end') {
+            accu.push(buffer);
+            // Clear buffer
+            buffer = [];
+        }
+
+        return accu;
+    }, []);
+}
+
+function isQuiz(nodes) {
+    // Extract potential questions
+    var questions = splitQuestions(
+        // Skip quiz title if there
+        nodes.slice(
+            (nodes[0] && nodes[0].type) === 'paragraph' ? 1 : 0
+        )
+    );
+
+    // Nothing that looks like questions
+    if(questions.length === 0) {
+        return false;
+    }
+
+    // Ensure all questions are correctly structured
+    return _.all(questions, isQuestion);
+}
+
+module.exports = isQuiz;