Enter, exit and update by datasets. Using as a component (Angular, React, ...).
forked from hironow's block: D3 linepoints chart by datasets
https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js
https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.10.1/lodash.min.js