better error handling, fix #20

- provide error handling for callback
- provide default error handling if no callback is passed

lib/index.js

@@ -48,14 +48,27 @@ function getRepo(options) {
  * Push a git branch to a remote (pushes gh-pages by default).
  * @param {string} basePath The base path.
  * @param {Object} config Publish options.
- * @param {Function} done Callback.
+ * @param {Function} callback Callback.
  */
-exports.publish = function publish(basePath, config, done) {
+ /*eslint-disable no-console */
+exports.publish = function publish(basePath, config, callback) {
   if (typeof config === 'function') {
-    done = config;
+    callback = config;
     config = {};
   }
 
+  var done = function(arguments) {
+    try {
+      (callback || function(err) {
+        if (!err) {
+          console.log(err)
+        }
+      })(arguments);
+    } catch (err) {
+      console.error('errors during calling the callback: ', err);
+    }
+  }
+  
   var defaults = {
     add: false,
     git: 'git',