"Observable is obnoxious if you want to add a D3 pie chart to your Vue application and have to untangle calls to D3’s API from reactive cell values, which look like ordinary JavaScript, but are not, and will cause compilation and runtime errors when copied."

Yep - as I wrote: "If you want to just blindly copy and paste d3 code, you may have issues with the docs being hosted on observable."

If instead you learn the core api (selections, bindings, and update patterns), any chart is really just a matter of using the correct layout/generator.

Here's d3 pie: https://d3js.org/d3-shape/pie

No need for going into Observable at all, as the pie generator is completely documented.

But if, as you mentioned, you prefer to copy the code from Observable, the linked pie example is extremely simple to do so: https://observablehq.com/@d3/donut-chart/2

Zero reactive cells, you can literally just copy the code inside the cell statement (e.g. the curly braces).