Javascript变量范围问题

我有一个变量mutedUser，我希望它能持久化到另一个函数。我在click事件外部持久化变量时遇到了一些问题。根据if语句的条件，“return mutedUser”保持“muted”字符串加法的最佳方式是什么？谢谢

*console.log让我检查持久性停止的位置

this.isUserMuted = function isUserMuted(payload) {
  var mutedUser = '';
  // If mute button is clicked place them into muted users list
  // check for duplicates in list
  $("#messages-wrapper").off('click', '.message button.muteButton');
  $("#messages-wrapper").on('click', '.message button.muteButton', function(e) {

      $('#unMute').show();

      //create userId reference variable
      var chatUserID = parseInt($(this).parent().parent().attr("data-type"));

      //store userId in muted user object
      mutedUsers[chatUserID] = {};
      mutedUsers[chatUserID].id = chatUserID;
      mutedUsers[chatUserID].muted = true;

      if (mutedUsers[chatUserID] !== null && mutedUsers[chatUserID].id === payload.a) {
          console.log("user is now muted");
          mutedUser += ' muted';
          console.log(mutedUser + 1);
      }
      console.log(mutedUser + 2);
  });
  return mutedUser;
};

编辑

对不起，我弄错了。另一种方法是传入该变量，即

this.isUserMuted = function isUserMuted(payload, isMuted) {
  isMuted = '';
  // If mute button is clicked place them into muted users list
  // check for duplicates in list
  $("#messages-wrapper").off('click', '.message button.muteButton');
  $("#messages-wrapper").on('click', '.message button.muteButton', function(e) {

      $('#unMute').show();

      //create userId reference variable
      var chatUserID = parseInt($(this).parent().parent().attr("data-type"));

      //store userId in muted user object
      mutedUsers[chatUserID] = {};
      mutedUsers[chatUserID].id = chatUserID;
      mutedUsers[chatUserID].muted = true;

      if (mutedUsers[chatUserID] !== null && mutedUsers[chatUserID].id === payload.a) {
          console.log("user is now muted");
          isMuted += ' muted';
          console.log(mutedUser + 1);
      }
      console.log(mutedUser + 2);
  });
  return isMuted;
};

---

如果我（通过查看代码）理解了您的意图，这将是最好的方法：

// If mute button is clicked place them into muted users list
// check for duplicates in list
$("#messages-wrapper").off('click', '.message button.muteButton');
$("#messages-wrapper").on('click', '.message button.muteButton', function(e) {
    $('#unMute').show();

    //create userId reference variable
    var chatUserID = parseInt($(this).parent().parent().attr("data-type"));

    //store userId in muted user object
    mutedUsers[chatUserID] = {};
    mutedUsers[chatUserID].id = chatUserID;
    mutedUsers[chatUserID].muted = true;
});

this.isUserMuted = function isUserMuted(payload) {
  var mutedUser = '';

  if (mutedUsers[payload.a] !== null) {
      mutedUser += ' muted';
  }

  return mutedUser;
};

代码保留

mutedUsers

数组，并且

isUserMuted

函数检查提供的用户是否在该数组中。在您提供的代码中，您将在每次调用

isusermute

函数时附加一个新的事件处理程序

isusermute

功能甚至可以缩短为：

this.isUserMuted = function isUserMuted(payload) {
  return mutedUsers[payload.a] !== null ? ' muted' : '';
};

---

你不能。如果您从函数返回字符串，它将始终按值传递，即复制；它的价值不会再改变了。您需要返回一个可以访问局部变量当前值的函数，或者返回一个属性正在更改的对象

由于您似乎已经有了一个对象，选项2将非常适合这里：

function User() { // or whatever you have
    …

    var user = this;
    // If mute button is clicked place them into muted users list
    // check for duplicates in list
    $("#messages-wrapper").on('click', '.message button.muteButton', function(e) {

        $('#unMute').show();

        //store userId in muted user object
        mutedUsers[user.id] = user;
        user.muted = true;
    });
    this.muted = false;
    this.isUserMuted = function() {
        return this.muted ? ' muted' : '';
    }
}

---

事实上，你原来的版本更好。新版本不行，你知道你是对的。但我通常将其视为一种模块模式，也就是说，类似这样的东西帮助我更好地理解了这个问题，这将非常有效，但是我需要在这个.isUserMuted函数的范围内使用变量“chatUserID”。这是因为，该变量基于一个单击事件，该事件检查在您的实现中加载的HTML中的一个属性，

chatUserID

实际上等于

payload.a

if用户确实被静音（根据您的if语句判断-

if（mutedUsers[chatUserID]！==null&&mutedUsers[chatUserID].id==payload.a）

这一行

mutedUsers[chatUserID].id=chatUserID；

在单击处理程序中）啊！一旦我将其设置为vs.！==谢谢你的帮助！没问题。我很高兴我能帮助你！检查NOTNULL和id的if语句是否有效？此外，您还可以这样做并发布结果：console.log（mutedUser+'muted1'）；