title: Filter react-admin query by dates
body: <p>I am using <code>react-admin</code>'s <a href="https://marmelab.com/react-admin/Actions.html#specialized-hooks" rel="nofollow noreferrer"><code>useGet...</code></a> query to gather data from my rails backend. The main problem here is the filter property (the last pair of curly braces in the useGetList operation). How can i filter the data by Dates (like get only transactions of the last month etc.) </p>
  
  <p><strong>This is the current (working) approach:</strong></p>
  
  <pre><code>const { data, loading, error } = useGetList(
      'transactions', 
      { page: 1, perPage: 10000 }, 
      { field: 'id', order: 'ASC' }, 
      {},
  )
  if (loading) return &lt;p&gt;Loading&lt;/p&gt;
  if (error) return &lt;p&gt;Error&lt;/p&gt;
  if (!data) return null
  </code></pre>
  
  <p>The entries in the database all have a <code>createdAt</code> and <code>updatedAt</code> property. </p>
  
  <p><strong>My approach would be to create a filter like this:</strong></p>
  
  <pre><code>// constraints could be dates that I can easily set beforehand
  { 
      {'createdAt', desiredLowerTimeConstraint, operation: '&lt;='}, 
      {'createdAt', desiredUpperTimeConstraint, operation: '&lt;='} 
  }
  </code></pre>
  
  <p>The <code>react-admin</code> <a href="https://github.com/marmelab/react-admin/tree/master/docs" rel="nofollow noreferrer">documentation</a> is quite sparce with the filter property, I couldn't find good examples for how these objects are supposed to look like.</p>