ACE editor: how to detect which block changed

Question

I am looking for a way to detect in which block my change occurred.

I'm writing a small markdown parser and want a simple UI, in order to keep positions and performance I only want the live preview to update the part I'm actually changing. For this to work I need to know which part in the ace editor I'm modifying.

When I use the onchange event the event data neatly specifies where my change occurred, which line and position. Before I start writing code which searches up and down for linebreaks I wanted to ask if there is a default way in the API to return which block changed.

You'll get something like this:

fs.readFile(__dirname + '/example.md', 'utf8', function(err, text) {
    session = ace.createEditSession(text);
    session.on('change', function(e, f) {
        // getChangedParagraph does not exist and needs to return the 
        // actual block which changed.
        var changedText = getChangedParagraph();
        parseTheText(changedText);
    });
    editor.setSession(session);
});

Answer 1

There is no concept of blocks in ace. ace change events give line and column of change, You need to keep track of positions in the parser