Patch based middleware for atomic actions

middleware.js

import { recordPatches } from "mobx-state-tree"

const runningActions = new Map()

export function atomicAsyncPatch(call, next) {
    switch (call.type) {
        case "action":
            return atomic(call, next)
        case "process_spawn": {
            const recorder = recordPatches(call.tree)
            runningActions.set(call.id, recorder)
            break
        }
        case "process_resume":
        case "process_resume_error": {
            const recorder = runningActions.get(call.id)
            recorder.resume()
            try {
                return next(call)
            } finally {
                recorder.stop()
            }
        }
        case "process_throw":
            runningActions.get(call.id).undo()
            runningActions.delete(call.id)
            break
        case "process_return":
            runningActions.delete(call.id)
            break
    }
    return next(call)
}