index.js

'use strict';
require('env2')('.env');
const amazon = require('amazon-product-api');

var client = amazon.createClient({
    awsId: "ID",
    awsSecret: "SECRET",
    awsTag: "TAG"
});

exports.handler = function (event, context, callback) {
  const barcode = event.params.querystring.barcode;
  if(!barcode || isNaN(parseInt(barcode)))
    return callback(null, []);

  client.itemSearch({
    keywords: barcode,
    searchIndex: 0
  });
  client.itemLookup({
    idType: 'EAN',
    itemId: barcode,
    responseGroup: 'ItemAttributes,Images',
    domain: 'webservices.amazon.co.uk'
  }).then(function(amazonResults) {
    if(!amazonResults.length || amazonResults.length < 1) 
      return callback(null, []);

    var items = amazonResults.filter(function(itemDetails) {
      return itemDetails.ItemAttributes[0];
    }).map(function(itemDetails) {
      var itemAttrs = itemDetails.ItemAttributes[0];
      return {
        barcode : barcode,
        source : "amazon",
        dateFetched : Date.now(),
        title :  (itemAttrs.Title) ? itemAttrs.Title[0] : undefined,
        productAmount : (itemAttrs.PackageQuantity) ? itemAttrs.PackageQuantity[0] : undefined,
        image_url : (itemDetails.MediumImage) ? itemDetails.MediumImage[0].URL[0] : undefined,
        price : (itemAttrs.ListPrice) ? itemAttrs.ListPrice[0].FormattedPrice[0] : undefined,
        releaseDate : (itemAttrs.ReleaseDate) ? itemAttrs.ReleaseDate[0] : undefined
      };
    });
    return callback(null, items);
  }).catch(function(err) {
    console.log(err);
    return callback(err);
  });
};