title: Is an empty string a valid JSON key?
body: <p>Is a JSON object having an empty string as a key valid, for example <code>{ "c": "x", "": "y" }</code>?</p>
  
  <p>It certainly seems to be, or at least it doesn't seem to break the web if I using it in a browser as per <a href="https://jsfiddle.net/v9ogfebk/" rel="noreferrer">this jsfiddle</a> having the following code:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var a = { "a": "x", "b": "y" };
  var b = { "c": "x", "": "y" };
  var c = JSON.stringify(a);
  var d = JSON.stringify(b);
  console.log(c);
  console.log(d);
  var e = JSON.parse(c);
  var f = JSON.parse(d);
  console.log(e);
  console.log(f);</code></pre>
  </div>
  </div>
  </p>
  
  <p>There is a good reason why I need (want) to use an empty string for a key, but am I just asking for trouble, in terms of browser compatibility and future-proofing?</p>