4 files changed, 32 insertions, 2 deletions
diff --git a/lib/output/generateBook.js b/lib/output/generateBook.js
index 6fcade0..f17997c 100644
--- a/lib/output/generateBook.js
+++ b/lib/output/generateBook.js
@@ -4,6 +4,7 @@ var Immutable = require('immutable');
 var Output = require('../models/output');
 var Config = require('../models/config');
 var Promise = require('../utils/promise');
+var fs = require('../utils/fs');
 
 var callHook = require('./callHook');
 var preparePlugins = require('./preparePlugins');
@@ -164,6 +165,17 @@ function generateBook(generator, book, options) {
             generator: generator.name
         })
     )
+
+    // Cleanup output folder
+    .then(function(output) {
+        var logger = output.getLogger();
+        var rootFolder = output.getRoot();
+
+        logger.debug.ln('cleanup folder "' + rootFolder + '"');
+        return fs.ensureFolder(rootFolder)
+            .thenResolve(output);
+    })
+
     .then(processOutput.bind(null, generator))
 
     // Log duration and end message
diff --git a/lib/plugins/listBlocks.js b/lib/plugins/listBlocks.js
index f738937..3ac28af 100644
--- a/lib/plugins/listBlocks.js
+++ b/lib/plugins/listBlocks.js
@@ -10,7 +10,8 @@ function listBlocks(plugins) {
     return plugins
         .reverse()
         .reduce(function(result, plugin) {
-            return result.merge(plugin.getBlocks());
+            var blocks = plugin.getBlocks();
+            return result.merge(blocks);
         }, Immutable.Map());
 }
 
diff --git a/lib/plugins/loadPlugin.js b/lib/plugins/loadPlugin.js
index 276d201..9ed83a1 100644
--- a/lib/plugins/loadPlugin.js
+++ b/lib/plugins/loadPlugin.js
@@ -73,7 +73,7 @@ function loadPlugin(book, plugin) {
         // Update plugin
         return plugin.merge({
             'package': Immutable.fromJS(packageContent),
-            'content': Immutable.fromJS(content)
+            'content': Immutable.fromJS(content || {})
         });
     })
 
diff --git a/lib/utils/fs.js b/lib/utils/fs.js
index 3f97096..da22fdb 100644
--- a/lib/utils/fs.js
+++ b/lib/utils/fs.js
@@ -129,6 +129,22 @@ function pickFile(rootFolder, fileName) {
     return undefined;
 }
 
+/**
+    Ensure that a directory exists and is empty
+
+    @param {String} folder
+    @return {Promise}
+*/
+function ensureFolder(rootFolder) {
+    return rmDir(rootFolder)
+    .fail(function() {
+        return Promise();
+    })
+    .then(function() {
+        return Promise.nfcall(mkdirp, rootFolder);
+    });
+}
+
 module.exports = {
     exists: fileExists,
     existsSync: fs.existsSync,
@@ -148,5 +164,6 @@ module.exports = {
     download: download,
     uniqueFilename: uniqueFilename,
     ensureFile: ensureFile,
+    ensureFolder: ensureFolder,
     rmDir: rmDir
 };