Play Action that implements provides web service for editor.js that discards the 'a' character.

CanadianEditor.scala

def text = Action(parse.json) { request =>
    val caret = (request.body \ "caret").as[Int]
    val text = (request.body \ "text").as[String]
    val trimmed = text.filterNot(_ == 'a')

    Ok(Json.obj("caret" -> (caret-(text.length-trimmed.length)), "text" -> trimmed))
}