命令模式 - 更复杂的情况 - 行为类模式 - [: '编程的套路 - JavaScript设计模式' |cut:tmp.cut_limit :]

示例参考 - ES5

<script>
  function Teacher(lessonPlan) {
    this.fullAttendence = true;
    this.lessonPlan = lessonPlan;
    this.absentPlan = [[], [], [], [], [],];
    this.additionalPlan = [[], [], [], [], [],];
  }

  function ReassignTeacherCommand(t1, t2, day) {
    this.t1 = t1;
    this.t2 = t2;
    this.day = day;
  }

  ReassignTeacherCommand.prototype.do = function () {
    this.t2.additionalPlan[this.day] =
      this.t1.absentPlan[this.day] =
        this.t1.lessonPlan[this.day];
  }

  ReassignTeacherCommand.prototype.undo = function () {
    this.t1.absentPlan[this.day] = [];
    this.t2.additionalPlan[this.day] = [];
  }

  function LeaveCommand(teacher, replacer, day) {
    this.teacher = teacher;
    this.reassign = null;
    this.replacer = replacer;
    this.day = day;
  }

  LeaveCommand.prototype.do = function () {
    this.teacher.fullAttendence = false;

    console.log('请假成功');
    this.reassign = new ReassignTeacherCommand(this.teacher, this.replacer, this.day);
    this.reassign.do();
  }

  LeaveCommand.prototype.undo = function () {
    this.teacher.fullAttendence = true;

    console.log('撤销请假');
    this.reassign.undo();
  }

  var whhPlan = [
    ['09:30'],
    ['09:30', '14:30'],
    [],
    [],
    ['15:00'],
  ];
  var lsdPlan = [
    ['09:30'],
    [],
    [],
    [],
    ['15:00'],
  ];

  var whh = new Teacher(whhPlan);
  var lsd = new Teacher(lsdPlan);
  var leave = new LeaveCommand(whh, lsd, 1);

  leave.do();

  console.log('whh:', whh)
  console.log('lsd:', lsd)

  leave.undo();

  console.log('whh:', whh)
  console.log('lsd:', lsd)
</script>