Dotted member path "@{0}" is invalid.
Occurs when there is a syntax error when attempting to extract a param value from the data object.
Here's an example of valid syntax for params or paramsDefault:
{
  bar: '@foo.bar'
}
The part following the @, foo.bar in this case, should be a simple
dotted member lookup using only ASCII identifiers.  This error occurs
when there is an error in that expression.  The following are all syntax
errors
| Value | Error | 
|---|---|
| @ | Empty expression following @. | 
| @1.a | 1is an invalid javascript identifier. | 
| @.a | Leading .is invalid. | 
| @a[1] | Only dotted lookups are supported (no index operator) |