title: Add field to CosmosDB item with Javascript SDK Error: Entity with the specified id does not exist in the system
body: <p>I am trying to add a new field to a CosmosDB item. The Field i want to add is an object.
  For example:</p>
  <pre><code>jobResult = { 
      description: &quot;exampledescription&quot;,
      value: &quot;examplevalue&quot;
  }
  </code></pre>
  <p>I tried the following code:</p>
  <pre><code>...
  const { CosmosClient } = require(&quot;@azure/cosmos&quot;);
  const endpoint = &quot;VALUE&quot;;
  const key = &quot;VALUE&quot;;
  const client = new CosmosClient({ endpoint, key });
  const { database } = await client.databases.createIfNotExists({ id: 'VALUE' });
  const { container } = await database.containers.createIfNotExists({ id: 'VALUE' });
  
  const operation = [ { op: &quot;Add&quot;, path: &quot;/result&quot;, value: jobResult } ];
  const { resource: updated } = await container.item(id = '42', partitionKeyValue = '/id')
                                               .patch(operation);
  ...
  </code></pre>
  <p>I get the error:</p>
  <blockquote>
  <p>Entity with the specified id does not exist in the system</p>
  </blockquote>
  <p><strong>The item exists because i get the item when using container.item(&quot;42&quot;).read()</strong></p>