I want to select Math! node when pressing backspace at the beginning of Paragraph 2. I tried to use $from.nodeBefore but it return null because there is no node before the current depth (1). How to get this node? path shows:

so the current node is the node with index 2 in the doc node. How to get this 2 from resolved positioned so that I could pick no at index 1 (doc.child(1)) from doc which is the desired math node?

Check that $from.index(-1) is > 0 and then take $from.node(-1).child($from.index(-1)). Or even loop up the tree from $from (looping depth from $from.depth to 0) to check whether there is a math node right in front of the position (and stopping if thereâ€™s other stuff before it at any level).

Shouldnâ€™t it be $from.node(-1).child($from.index(-1) - 1);? Because $from.node(-1).child($from.index(-1)) returns the same node. I understand it in such a way that $from.node(-1) returns the parent node (i.e. doc) and then using child($from.index(-1) - 1) we can get the previous child node. Before you replied I did the following:

let index = $from.index($from.depth - 1);
let pos = $from.posAtIndex(index - 1, $from.depth - 1);
let node = state.tr.doc.nodeAt(pos);
if (
node?.type.name === "math_display" &&
pos + node?.nodeSize! + 1 === $from.pos
) {
view.dispatch(
state.tr.setSelection(NodeSelection.create(state.tr.doc, pos))
);
return true;
}
return false;

Are these solutions equivalent and is my code correct?

Note that your code wonâ€™t work if thereâ€™s, for example, a list wrapping the block with the cursor, because then youâ€™d need to go up multiple levels.