D3 Cook Book getting used to JS in d3 CH2 Problem in converting from v3 to v5 and looks like book has poor practice of d3.js (https://stackoverflow.com/questions/45181773/d3-js-raw-selection-get-error-uncaught-typeerror-cannot-read-property-0-of-u) This version is an attempt to put into the ProD3.js resusable pattern