Javascript: Passing variable into ShopifyApp initialize

Question

I'm building a we app which uses the Shopify Embedded App SDK. I'm trying to extract a param from the request url, and passing this into a javascript initialize function for the embedded app. However the captured variable doesn't insert as expected.

I can successfully capture the params from the request, however the variable never outputs within the initialize function.

Here's my code so far:

<script src="//cdn.shopify.com/s/assets/external/app.js?123445566"></script>

<script type="text/javascript">
//Capture the params from the URL = Works fine
var urlParams;
(window.onpopstate = function () {
    var match,
        pl     = /\+/g,  // Regex for replacing addition symbol with a space
        search = /([^&=]+)=?([^&]*)/g,
        decode = function (s) { return decodeURIComponent(s.replace(pl, " ")); },
        query  = window.location.search.substring(1);

    urlParams = {};
    while (match = search.exec(query))
       urlParams[decode(match[1])] = decode(match[2]);
})();

//This is the part I am having troubles with, the urlParams["shop"] just outputs "urlParams["shop"]" instead of the value
ShopifyApp.init({
    apiKey: "thiscontainsthecorrectapikeyvalue",  // Expects: 32 character API key string like ff9b1d04414785029e066f8fd0465d00
    shopOrigin: 'https://' + urlParams["shop"],  // Expects: https://exampleshop.myshopify.com
    debug: true
  });

//This alert works as expected, and shows the correct value: "exampleshop.myshopify.com"
alert(urlParams["shop"]);
</script>

I can use plain javascript or jquery, but please note I am noob to both, mainly familiar with rails (which I cannot use in this particular page).

Any ideas on how to pass the captured param into the initialize function?

Answer 1

Not sure but can be the problem of asynchronous concept, use the urlParams after made it.

(window.onpopstate = function () {
      ......
      ......
      urlParams = {};
      while (match = search.exec(query)){
          urlParams[decode(match[1])] = decode(match[2]);
      }

      callInit(urlParams); //use when it is made
})();

function callInit(urlParams){
    ShopifyApp.init({
        apiKey: "thiscontainsthecorrectapikeyvalue", //API Key
        shopOrigin: 'https://' + urlParams["shop"],
        debug: true
      });

}