about scroll sync

[shd101wyy]

Hello,

Right now I am trying to implement the scroll sync feature for a markdown editor.

Suppose I have the .md file with content below

### Hello  
this is a markdown file

which produces the html code

<h3>Hello</h3>
<p>this is a markdown file</p>

So I want to map the generated html dom element with my markdown content.
for example, I want the html code to be

<h3 data-line="0">Hello</h3>
<p data-line="1">this is a markdown file</p>

where data-line="0" in <h3 data-line="0">Hello</h3> is from the 0th line of the markdown, which is ### Hello.

data-line="1" in <p data-line="1">this is a markdown file</p> is from the 1th line of the markdown, which is this is a markdown file.

Basically, I want to make a sourcemap (I am not so sure if I am using the correct term though)

Could please give me some suggestions how to do it.

Thank you.

[Feder1co5oave]

See #680