Observable

Product page

To only drawn the text once you can use the select transform:

Plot.text(data, Plot.selectFirst({
  x: 0.1,
  y: 12,
  textAnchor: "start",
  text: (d) => d.date.toLocaleString("en", {month: "long"})
}))

Also I recommend using English rather than the browser’s locale since the rest of the page is in English already and it looks odd to mix locales.

Mike Bostock

ooh - thank you! 

And, thank you for the suggestion / update regarding Locale string! I copy/pasted from a stackoverflow answer and only briefly wondered what the 'undefined' was doing :). Good learning for the future too.