Grid table colour change based on date

So one of the issues with doing the formatting based on date is that dates are always changing including the comparison start date.  There is a need to get the data in a start of semi fixed values so the state based formatter can work.  For the example below I query my fridge for the fridge temperature history, which gives me the results( id, timestamp, value ).  Then add a new column called "DateDiff" which just so happens to match my return data shape named "FridgeTempHistoryWithDateOffset".   Then loop through the results comparing the dates of the property history to now.  This will give the comparison value to use in state based formatting.

// result: INFOTABLE dataShape: "NumberValueStream"
result = Things["TestFridge2"].QueryNumberPropertyHistory({
	oldestFirst: false, maxItems: 100, propertyName: "fridgeTemp",});

// add date diff column
result.AddField( { name: "DateDiff", baseType: 'NUMBER'} );

let dNow = new Date();

// only done for illustration purposes.
result.rows[0].timestamp = dNow;
result.rows[1].timestamp = dNow - ( 1000 * 3600 * 24 );

result.rows.toArray().forEach( row => {
 row.DateDiff = ( dNow.getTime() - row.timestamp )/( 1000 * 3600 * 24 );
});

Since in theory I am not interested in the DateDiff column in my display I remove it from showing in the grid but still use the value for formatting.  Using the results from the above service, I can get the attached output.  Not the grid on the right shows DateDiff just for visual reference.

Thanks,