JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
 <ul>
  <li data-id=1 data-gameresult=2:0></li>
  <li data-id=3 data-gameresult=1:0></li>
  <li data-id=4 data-gameresult=0:0></li>
  <li data-id=5 data-gameresult=1:3></li>
 </ul>

JavaScript

var json = {
   gameResults: []
};

$("li").each(function (i, li) {
   json.gameResults.push({
       id: $(li).data('id'),
       gamescore: $(li).data('gameresult')
   });
});

alert(JSON.stringify(json));