Field Mapping for Reach Data Streams

It’s important to map the day and reach fields correctly in a reach data stream. The mapping can vary depending on the granularity that you’re setting up. Only map the required fields.

Mapping the Day field for reach data:

For a 31-day granularity, the formula for the day field is:
```
Day = csv['fb.date_stop']
```

For a 7-day granularity, the formula for the day field is:

Day = var date = csv['fb.date_stop'];
var dayofweek = FORMATDATE(date, 'u');
if(dayofweek != 1)
{diff = dayofweek-1;
return date = DATEADD('d',-diff,date);}
else {return date;}

Mapping the Reach measurement for reach data:

```
Reach = csv['fb.reach']
```