title: Data Factory: JSON data is interpreted as expression - ErrorCode=InvalidTemplate, ErrorMessage=Unable to parse expression
body: <p>I want to copy items from </p>
  
  <p><em>CosmosDB database<strong>A</strong>/productCollection</em></p>
  
  <p>to </p>
  
  <p><em>CosmosDB database<strong>B</strong>/productCollection</em></p>
  
  <p>Therefore I decided to use Azure Data Factory.
  I actived also "Export as-is to JSON files or Cosmos DB collection".</p>
  
  <p>The read operation works as expected.<br>
  Unfortunately, the write operation stops because of an error related to the data:</p>
  
  <blockquote>
    <p>ErrorCode=InvalidTemplate, ErrorMessage=Unable to parse expression 'Currency'</p>
  </blockquote>
  
  <pre><code>{
  "ProductName": "Sample",
  "Price": {
      "@Currency": "GBP",
      "$": "2624.83"
  }
  </code></pre>
  
  <p>}</p>
  
  <p>I'm not able to change to input data itself.
  The output data has to equal the input data.</p>
  
  <p>Is there possiblity, that <em>@Currency</em> will not be interpreted as an expression</p>
  
  <p>In ARM, this part is failling:  </p>
  
  <blockquote>
    <p>Price.{@Currency}</p>
  </blockquote>