[fix] refactor reduce loop.

lib/complete.js

@@ -27,7 +27,7 @@ function complete(options) {
   if (process.platform === 'win32') return;
 
   options = options || {};
-  commands = options.commands || exports.commands;
+  commands = options.commands || exports.commands || {};
   opt = options.options || exports.options;
   program = options.program || exports.program;
 
@@ -59,21 +59,25 @@ function complete(options) {
 function completeWords() {
   var cur = words[words.length-1]
     , prev = words[words.length-2]
-    , com = commands
-    , command = com
+    , command = commands
+    , l = words.length
     , i = 1
+    , word
     , out;
 
   // Reduce
-  while (com) {
-    if (Array.isArray(com)) {
-      if (~com.indexOf(words[i++])) {
+  for (; i < l; i++) {
+    word = words[i];
+    if (Array.isArray(command)) {
+      if (~command.indexOf(word)) {
         command = true;
       }
       break;
     } else {
-      if (com = com[words[i++]]) {
-        command = com;
+      if (command[word] && hop.call(command, word)) {
+        command = command[word];
+      } else {
+        break;
       }
     }
   }
@@ -85,7 +89,7 @@ function completeWords() {
       : command(words, output);
   } else if (command) {
     // Already matched
-    if (i === words.length + 1) {
+    if (i === l) {
       echo(cur);
       return;
     }
@@ -273,6 +277,8 @@ function output(key, list) {
   return echo(match(key, list));
 }
 
+var hop = Object.prototype.hasOwnProperty;
+
 /**
  * Callback Style
  * Expose a lower level