Data accessor function or property name for extracting a value from a D3 datum. If a string is provided, it's used as a property key on the datum object. If a function is provided, it receives the datum and its index, returning the value.
Data accessor function or property name for extracting a value from a D3 datum. If a string is provided, it's used as a property key on the datum object. If a function is provided, it receives the datum and its index, returning the value.