woocommerce api get request returns -1 as response node js

My

WooCommerce.get('orders', function(err, data, res){ 
console.log(res) }

returns

-1

as the response. My authentication seems to be set up correctly as such.

var WooCommerceAPI = require('woocommerce-api');
var Woocommerce = new WooCommerceAPI({ 
url: 'https://example.com',
consumerKey: 'ck-xxxxxxxxxxx',
consumerSecret: 'cs-xxxxxxxxxx',
wp-api: true,
version: 'wc/v1'
});

Please help I don't understand what I am doing wrong here.

via s.renton