I think there are inevitably limitations to what can be done with the formatters etc. However, there seem to some anomalies when dealing with expressions which could be created at least partly with the formatters. I’m not sure if the cases below are just limitations or (fairly minor) bugs.
If I want to create an expression like this, using the Data bindings/Formats panel:
… I add ‘[$index]’ manually, but then I should be able to use the formatters. However, as far as I can see, I have to convert the expression to a string, continue modifying the expression, and then edit the expression - to remove ‘toString()’. Including ‘$index’ means that only numeric options are available (obviousy I don’t want to apply any formatting to ‘$index’ itself):
Another issue is editing expressions including regular expressions. I appreciate that the regex has to be added manually, but it would be useful to use the formatters too. Eg this expression can’t be edited using the Data Formats panel at all, although the options are available in the Data Formats panel:
sc_detail.data.qry_item.author.replace(/\[.*?\]/, '').slugify().replace('-', ' ')
… this error appears if I try: