Set Border Position.sketchplugin

var doc = context.document;
var sel = context.selection;

var borderPosition = doc.askForUserInput_initialValue_( 'Set Border Position: 0:Center / 1:Inside / 2:OutSide', '' );
if ( !borderPosition || '' == borderPosition || ( 0 > borderPosition || 2 < borderPosition ) ) return false;

for ( var i = sel.count() - 1; i >= 0; i-- ) {
	var border = sel[i].style().borders();
	border.objectAtIndex(0).setPosition( borderPosition );
};