// common

import Deliveryman from 'deliveryman';

const deliveryman = new Deliveryman();

// from iframe

deliveryman.send('package', { name: 'huawei p30 pro', price: '￥6000' });

// from main page

deliveryman.delivering('package', function(package) {
    console.log(package);
});

// or u can just use receive

const package = deliveryman.receive('package');