Feature request: Node depth

I see this being mostly useful for blocks, but for consistency I would add it to any node. A clear example where it’s useful:

type: unordered-list
    type: list-item
        type: text
        type: unordered-list
            type: list-item

Now imagine you’re working on a list plugin (I am) and you need to figure out how to handle a <TAB> keypress. You need to look at the depth of the current item and the parent item (or in this case parent of parent) to figure out if you can actually go one step “deeper” (i.e. wrap in another unordered-list.)

I would be happy to work on a PR, though I need a tiny bit of guidance, if you feel this is useful. I would add a depth<Number> to most of the models and at some point in the code figure out where to add this. Could be an extensive PR I guess. Happy to get pointers!

[mull]

I should be ashamed.

[ianstormtaylor]

Actually there is a getDepth(descendant) on Node already too 😃