specialCharPlaceholder / specialChars on multiple character

How is it possible to replace multiple characters in Codemirror (while typing) to another character?

Say I want to replace => with a ligature, or an SVG. And also replace * with an x multiplication SVG.

  specialChars: /\*/,
  specialCharPlaceholder: () => {
    const node = document.createElement('i');
    // node.innerHTML = 'x';
    node.className = 'bp3-icon-standard bp3-icon-small-cross';
    return node;

With the combination of specialChars and specialCharPlaceholder I can do this. But as far as I can tell, I can only do it on one character?

How is it possible to give Codemirror a set of regexes that map to replacements?
I’m not sure specialCharPlaceholder is the correct way to do this or not.

This isn’t a feature that’s built in, but you could write an extension that does it (scan the viewport for matching sequences, replace them with a widget with markText, update on further changes).

Ok thanks, I’ll do that.

What exactly is the main use case for specialCharPlaceholder? I’m going over the docs and trying make sense of what some of the configs (in particular specialCharPlaceholder) are for.