Custom $ionicSideMenuDelegate, how to drag only from very left corner as in apps like Yelp, Hangouts, etc.?

I’m following this codepen:

There is a custom directive called can-drag-menu where if you drag the content right, the menu opens or closes.

However, if you have swipe content on the screen, the side menu opens up so you can drag even middle of the screen and the menu will open. How do you make the menu only open from the very left edge of the screen as in apps like Yelp/Hangouts/etc? I have to have my finger pretty much at the very left edge and drag right to open the menu.

Please let me know. Thanks