ionic package build android FAILED due to TypeError: Cannot read property 'length' of undefined

I just created a demo ionic project by ionic start conference, but when I tried to build the Android package, it tell me that TypeError: Cannot read property 'length' of undefined.

Then I tried to create another demo, ionic start blank, failed again.

ionic serve works all good and here is the information of ionic info

global packages:

@ionic/cli-utils : 1.1.2
Ionic CLI        : 3.1.2

local packages:

@ionic/app-scripts              : 1.3.7
@ionic/cli-plugin-ionic-angular : 1.3.0
Ionic Framework                 : ionic-angular 3.3.0

System:

Node       : v6.9.5
OS         : macOS Sierra
Xcode      : not installed
ios-deploy : not installed
ios-sim    : not installed

Is there any dependency problem?

via Joe