THE GENERAL UPDATE PATTERN - v5+ in reusable format

USING join() rather than merge().

MB alphabet example: https://bl.ocks.org/mbostock/3808234 https://bl.ocks.org/john-guerra/cabfbaed34d942e4dd81199855e4987f

A vanilla HTML implementation of Rob Moores updateable pattern Towards Updatable https://www.toptal.com/d3-js/towards-reusable-d3-js-charts.

It is derived from Mike Bostock's Towards Reusable Charts (https://bost.ocks.org/mike/chart/) as the source of the foundational principles.

UseS the ProD3 pattern (Pro D3.js Use D3.js to Create Maintainable, Modular, and Testable Charts by Marcos Iglesias https://www.apress.com/gp/book/9781484252024) as the basis for further charts.