next-task.js

lets(
  /* Store unfinished tasks */
  tasks, prop("Tasks").filter(current.prop("Status") != "Done"),
  
  /* Sort by timestamp of task and store with id */
  task, 
  tasks
    .map(formatDate(current.prop("Date"), "X") + "-" + current.id())
    .sort()
    .first(), 
  
  /* Explode stored id and find the task with that id */
  tasks
    .find(
      let(
        taskId, 
        task.split("-").last(), 
        current.id() == taskId
      )
    )
  )