• Prosemirror reference to Transaction class
• Prosemirror transform guide

Transactions happen at or with a certain Selection. Which can either be a TextSelection or a NodeSelection.

It is possible to build a complex action from several subactions. I'm not sure if this is the correct/best-practice way to do it.

        dispatch(state.tr
            .ensureMarks([])
            .insertText(prefix)
            .insertText(username)
            .addMark(
                usernameFrom,
                usernameTo,
                schema.marks.link.create({
                    href: `mailto:${usermail}`,
                }))
            .insertText(timestring)
            .addMark(
                usernameFrom,
                signatureEnd,
                schema.marks.em.create())
            .ensureMarks([]));