title: Sharepoint Online - JSON column formatting
body: <p>I have the following code given by Michael Han that is working just fine. It formats a number like '2030' to be '20:30'</p>
  
  <pre><code>{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "txtContent": {
      "operator": "+",
      "operands": [
        "=substring(toString(@currentField),0,2)",
        ":",
        "=substring(toString(@currentField),2,4)"
      ]
    }
  }
  </code></pre>
  
  <p>I need to use this column as a lookup column for another list, so I pasted this code and replaced <strong>@currentField</strong> with <strong>@currentField.LookupValue</strong> in the new lookup column as mentioned in <a href="https://github.com/SharePoint/sp-dev-docs/blob/master/docs/declarative-customization/column-formatting.md" rel="nofollow noreferrer">https://github.com/SharePoint/sp-dev-docs/blob/master/docs/declarative-customization/column-formatting.md</a></p>
  
  <p>The result is just showing "<strong>:</strong>". What do I have to do to make it work?</p>
  
  <p>Regards,
  Elio Fernandes</p>