JavaScript - 类型错误 : listener must be a function

Question

又一个“监听器必须是函数”错误。 我仔细检查了所有参数，检查了正确的语法等，但仍然找不到问题所在:

这是我的代码片段。

在login.js中:

global.eventEmitter = require('./helpers/EventEmitter.js');
var packetSwitch = require('./handlers/PacketSwitch.js');
global.ackHandler = require('./handlers/ACKPacketHandler.js');
...
global.eventEmitter.createAndFireEvent('opCodeReceived',packetSwitch.switch(opcode, decrypted, sock));

在 PacketSwitch.js 中:

var packetHandler = require('./PacketHandler.js');
exports.switch = function(opcode, data, sock) {
    switch (opcode) {
        case 1:
            eventEmitter.createAndFireEvent('reqLoginReceived', packetHandler.handleLoginReq(data, sock));
            break;
        case 2:
            eventEmitter.createAndFireEvent('reqDateReceived', packetHandler.handleDateReq(data, sock));
            break;
        default:
            eventEmitter.createAndFireEvent('unknownReceived', packetHandler.handleUnknown(data, sock));
    }
};

假设进入情况 2: 在PacketHandler.js中:

exports.handleDateReq = function(data, sock) {
    global.eventEmitter.createAndFireEvent('handleDateAck', global.ackHandler.handleDateAck(sock));
};

在 ACKPacketHandler.js 中:

exports.handleDateAck = function(sock) {
    sock.write("Test!");
};

在EventEmitter.js中:

var eventEmitter = require('events');
const myEmitter = new eventEmitter.EventEmitter();

exports.createAndFireEvent = function(event, callback) {
    myEmitter.on(event, callback);
    myEmitter.emit(event);
};

这是我收到的错误的屏幕截图: https://gyazo.com/6047c5917f937aa33f29f9fc40cdf5f7

Answer 1

您的数据包处理函数(例如handleDateAck())不是返回函数。事实上，他们似乎没有返回任何东西。返回值是您当前用作传递给 emitter.on() 的监听器函数的值。