How to replace currently selected content in ProseMirror

Question

A little lost in ProseMirror at the moment and trying to understand the correct way to replace the text of the current selection. I want to be able to toggle the case between lower/upper case.

state.selection.content(); will return slice of the relevant nodes under the selection, and the content that is selected, but does not return the range within each node that would need to replaced.

I assume I would need to create a new text node to replace the range within each selected node something like:

const updatedText = node.textContent.toUpperCase();
const textNode = state.schema.text(updatedText);
transaction = transaction.replaceWith(startPos, startPos + node.nodeSize, textNode);

How do I get the range to replace within each node?

Unfortunately, I cannot find a suitable example.

Answer 1

Ended up with the following that uses replaceWith.

May be a better solution, but hopefully this helps others.

See comments inline:

const execute = (casing, state, dispatch) => {
  // grab the current transaction and selection
  let tr = state.tr;
  const selection = tr.selection;

  // check we will actually need a to dispatch transaction
  let shouldUpdate = false;

  state.doc.nodesBetween(selection.from, selection.to, (node, position) => {
    // we only processing text, must be a selection
    if (!node.isTextblock || selection.from === selection.to) return;

    // calculate the section to replace
    const startPosition = Math.max(position + 1, selection.from);
    const endPosition = Math.min(position + node.nodeSize, selection.to);

    // grab the content
    const substringFrom = Math.max(0, selection.from - position - 1);
    const substringTo = Math.max(0, selection.to - position - 1);
    const updatedText = node.textContent.substring(substringFrom, substringTo);

    // set the casing
    const textNode = (casing === 'uppercase')
      ? state.schema.text(updatedText.toUpperCase(), node.marks)
      : state.schema.text(updatedText.toLocaleLowerCase(), node.marks);

    // replace
    tr = tr.replaceWith(startPosition, endPosition, textNode);
    shouldUpdate = true;
  });

  if (dispatch && shouldUpdate) {
    dispatch(tr.scrollIntoView());
  }
}