coin2html: js README update

cmd/coin2html/js/README.md

@@ -4,6 +4,10 @@ The overarching goal is to have everything packaged in a single html file, the d
 
 For the longest time I tried to avoid using a JS builder, just piecing the final HTML file together from the various bits here. However the un-modularized Typescript code was difficult to test. I had hopes for ES module support in the browser, but it turns out that inlined modules are useless, cannot be imported (without resorting to some ugly hacks), so eventually I gave up and introduced webpack. I picked webpack because of its HtmlBundlerPlugin that can produce a single HTML page bundling everything.
 
+D3 is the main workhorse of the app, it builds all the visual elements beyond the bare bones dom skeleton defined in body.html. That include not just the charts but the html tables as well. I'd like to stick with D3 as much as possible to keep dependencies to a minimum. I might be tempted to switch to Observable/Plot to reduce the amount of code given that at least some of the charts are pretty standard stock, we'll see, at the moment I'm having too much fun with D3.
+
+As it is the final html file for examples/yearly is ~7MB. This is after stopping importing D3 wholesale and importing just the bits that are used. It does include sourcemaps though to make debugging convenient. There's no minification yet either, which would presumably help as well.
+
 # Project structure
 
 The main pieces are