Accessing EJS variable in Javascript logic

I had the same problem. I needed to use the data not for just rendering the page, but in my js script. Because the page is just string when rendered, you have to turn the data in a string, then parse it again in js. In my case my data was a JSON array, so:

<script>
  var test = '<%- JSON.stringify(sampleJsonData) %>'; // test is now a valid js object
</script>

Single quotes are there to not be mixed with double-quotes of stringify. Also from ejs docs:

"<%- Outputs the unescaped value into the template"

The same can be done for arrays. Just concat the array then split again.

You could directly inject the gameState variable into javascript on the page.

<% if (gameState) { %>
     <h2>I have a game state!</h2>
     <script>
        var clientGameState = <%= gameState %>            
     </script>
<% } %>

Another option might be to make an AJAX call back to the server once the page has already loaded, return the gameState JSON, and set clientGameState to the JSON response.

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