Cannot read properties of undefined (reading 'thematicName')

This error occurs when you are trying to access the property 'thematicName' on an undefined object. It means that the object you are trying to access does not exist or has not been defined.

To fix this error, you need to ensure that the object is properly defined before accessing its properties. You can use conditional statements or null checks to ensure that the object exists before accessing its properties.

For example:

if (obj && obj.thematicName) {
  // Access the 'thematicName' property here
} else {
  // Handle the case when the object or 'thematicName' property is undefined
}

By checking if the object exists before accessing its properties, you can prevent this error from occurring.