title: How can I make "onload" waiting for "fetch" complete?
body: <p>Long story short, I'll show the code.</p>
  
  <p><strong>some.html</strong></p>
  
  <pre><code>&lt;html&gt;&lt;script src="some.js"&gt;&lt;/script&gt;&lt;/html&gt;
  </code></pre>
  
  <p><strong>some.js</strong></p>
  
  <pre><code>window.onload = () =&gt; console.log( "onload" );
  (async (url, cb) =&gt; cb( await ( await fetch(url) ).json() ))
  ( "some.json", () =&gt; console.log( "in async" ) );
  </code></pre>
  
  <p>and some.html outputs:</p>
  
  <pre><code>onload
  in async
  </code></pre>
  
  <p>I've done some works e.g. image loading in real fetch, so <code>fetch().then()</code> doesn't work for me.</p>
  
  <p>Now my question is as title says, how can I let "onload" waiting for "fetch" complete?</p>