What does this mean when babel transpiles a function call?

Question

I wrote this ES6 code in BabelJS.io embedded editor:

import { getNum } from './counter.js';
getNum(1)

And babel transpiles the above code into:

'use strict';

var _counter = require('./counter.js');

(0, _counter.getNum)(1);

Everything is clear except the last line (0, _counter.getNum)(1), I want to understand what it is, and how does it work to comply with the according ES6 code?