ebay.js

const baseURL = "https://onyx-elevator-270422.appspot.com/";

function getURL(parameters) {
  let url = new URL(baseURL);
  for (let [key, value] of Object.entries(parameters)) {
    url.searchParams.append(key, value);
  }
  return url.href;
}

function getJSON(url) {
  return fetch(url).then(response => response.json());
}

// Searchs eBay for items that match the given keyword. Returns these in an
// array of objects.
//
// REQUIRED PARAMS:
// keyword (string): the keywords to search for items with. this can be multiple
// words, just put a space between them in a single string
// results (integer): number of results to return
//
// OPTIONAL PARAMS:
// postalCode (integer): the postal code of the buyer
// maxRadius (integer): the maximum radius around the postalCode to search for
//
// Returns in this format:
//
function findItemsByKeywordsAndRadius(keyword, results, postalCode, maxRadius) {
  if (!keyword || !results) {
    return [];
  }

  let parameters = {
    "OPERATION-NAME": "findItemsByKeywords",
    "SERVICE-VERSION": "1.0.0",
    "SECURITY-APPNAME": "ebayhack-ecoBay-PRD-669e8f5f8-11393d83",
    "GLOBAL-ID": "EBAY-US",
    "RESPONSE-DATA-FORMAT": "JSON",
    keywords: keyword,
    "paginationInput.entriesPerPage": results
  };

  if (postalCode && maxRadius) {
    parameters["buyerPostalCode"] = postalCode;
    parameters["itemFilter(0).name"] = "LocalSearchOnly";
    parameters["itemFilter(0).value"] = true;
    parameters["itemFilter(1).name"] = "MaxDistance";
    parameters["itemFilter(1).value"] = 100;
  }

  let url = getURL(parameters);
  return getJSON(url).then(raw => {
    let rawItems = raw.findItemsByKeywordsResponse[0].searchResult[0].item;
    if (rawItems == undefined) {
      return [];
    } else {
      let newItems = [];
      for (let item of rawItems) {
        newItems.push({
          title: item.title[0],
          imageURL: item.galleryURL[0],
          location: item.location[0],
          price: parseFloat(item.sellingStatus[0].currentPrice[0].__value__),
          itemURL: item.viewItemURL[0]
        });
      }
      return newItems;
    }
  });
}

function findItemsByKeywords(keyword, results) {
  return findItemsByKeywordsAndRadius(keyword, results, null, null);
}

/*
EXAMPLE: prints out the top 5 results for 'shoes' on eBay:

findItemsByKeywords('shoes', 5).then((items) => {
    for (let item of items) {
        console.log(item);
    }
});

EXAMPLE: prints out the top 5 results for 'red shirt', with a radius of 10 miles
around the Zip Code 98195.

findItemsByKeywordsAndRadius('red shirt', 5, 98195, 10).then((items) => {
    for (let item of items) {
        console.log(item);
    }
});
*/