Cells ids

[neocarto]

In Observable notebooks 2.0, it’s possible to assign an id to a cell. But I don’t really understand what it’s for. What I would like is for it to be the id of the div on the page so that I can target it with CSS (for styling and positioning). Is it the idea of this PR? #103

[mbostock]

It’s mainly used to track the identity of cells for the benefit of the editor (Observable Desktop). It means if you edit a Notebook HTML file directly (using a text editor, or source control), Desktop can track how the cells moved, and be smarter about incrementally updating runtime state. This isn’t implemented yet, however, so the id attribute is just informational at this point.

The cell id is already used to assign the id attribute of the rendered HTML, with the cell- prefix added. Notebook cell identifiers are numeric, which isn’t a valid CSS identifier, so the cell id 42 is turned into the attribute cell-42, and you can use #cell-42 to select it via CSS.

[neocarto]

I understand. It would be interesting to allow non-numeric cell ids in order to have more relevant CSS selector names.