Format SharePoint List row based on empty column using json

Question

How do I extend the solution provided here to highlight a row if, say, column "LookUpColumnABC" is empty?

I tried incorporating if([$LookUpColumnABC] == '', if([$LookUpColumnABC] == "" and similar code into this solution but that's not working.

How do I check for the absence of a value and highlight the entire row?

Answer 1

Comparing to an empty string as you are showing is fine in most cases. But you can also use the length operator which seems to cover all cases equally well. I'm not sure everything you're trying to accomplish, but here's a very basic view format using this logic to make rows with empty values in the Lookup column red and others blue:

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/row-formatting.schema.json",
  "additionalRowClass": "=if(length([$Lookup])==0,'ms-bgColor-red','ms-bgColor-blue')"
}

length is used to determine the number of items in an array (not string length) and for anything other than arrays always returns 1 when a value is present and 0 when not.

Answer 2

You can use JSON like:

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/view-formatting.schema.json",
  "additionalRowClass": "=if([$LookUpColumn.lookupValue], if([$LookUpColumn.lookupValue] > 75, 'sp-field-severity--good', if([$LookUpColumn.lookupValue] < 75 && [$LookUpColumn.lookupValue] > 50, 'sp-field-severity--low', if([$LookUpColumn.lookupValue] < 50 && [$LookUpColumn.lookupValue] > 25,'sp-field-severity--warning', if([$LookUpColumn.lookupValue] < 25,'sp-field-severity--blocked', '')))), '')"
}

Example:

Here I am using the simple expression like:

if([$LookUpColumnABC.lookupValue], "Value available", "Value not available")

I am referring the "Simplest way" provided in this article: SharePoint JSON formatting: Check if column is blank/empty