If you want to use URL parameters in your notebooks (to prefill inputs and create permalinks), here’s a library for you: https://observablehq.com/@jerryjappinen/url-params

A pattern that I frequently use is

params = Object.fromEntries(new URL(document.baseURI).searchParams)

and then e.g.

viewof foo = Inputs.text({
  // ...
  value: params.foo ?? "some default"
})

Yup, that’s more or less what this does @Fabian Iwand. But a bit nicer to use across notebooks, and also parses numbers correctly

Fwiw when I need preset values other than strings I usually just JSON stringify/parse everything and store it in a single param