title: Cannot add property key, object is not extensible error Apollo Client with antd
body: <p>I get an error <code>Cannot add property key, object is not extensible</code> using <code>&quot;@apollo/client&quot;: &quot;^3.0.2&quot;</code> with ant design.</p>
  <p>I can successfully obtain data from the server with my graphql query, however, the problem is that, the data inside the return object is somehow unextendable. This never used to be a problem prior to using apollo client (using apollo boost).</p>
  <p>In order to make my data work in a table in ant design, I have to pass in the array data obtained from the <code>data</code> object returned from the server. The part where I get the error is when I attempt to iterate through the <code>items</code> array, and add a <code>key</code> to each object, so that react won't complain in the console of a missing <code>key</code> element for the html.</p>
  <pre><code>  const items = [...data.items];
    console.log(&quot;items:&quot;, items);
  
    // Add a key for each item to make React stop complaining
    // Erorr occurs here!!!
    items.forEach(item =&gt; {
      item.key = item.id;
    });
  </code></pre>
  <p>Is there a way we can remove this unnecessary functionality that's hindering our ability in modifying and extending results obtained from the server? Also I tried spreading the array making a deep copy, but that's not working either.</p>
  <p>What do I need to do to make sure that I can add an additional <code>key</code> field in each array item, based on the <code>id</code>?</p>
  <p>Addendum:</p>
  <p>I don't actually need the code that does the <code>items.forEach()</code> stuff. However, if I don't add it, react will complain that the entries in the table are all missing a <code>key</code> value. This is my workaround since tables in ant design get their data from an array of objects, and thus, need to have a <code>key</code> value in there. Since querying data from the server typically doesn't include a <code>key</code> property in an object, this has to be manually added.</p>