Question

您好我正在尝试像这样构建一个Node.js应用程序。我的app.js文件中的代码是：

var _ = require('underscore');
var employee = require('./employeeEmitter');
var EventEmitter = require('events').EventEmitter;
var emitter = new EventEmitter();
var inherits = require('util').inherits;
var data = [
    {id:1, firstName: 'John', lastName: 'Smith'},
    {id:2, firstName: 'Jane', lastName: 'Smith'},
    {id:3, firstName: 'John', lastName: 'Doe'}
];
inherits(employee.EmployeeEmitter, EventEmitter);
var newEmployeeEmitter = new employee.EmployeeEmitter(data);
newEmployeeEmitter.on('lookupById',function(){newEmployeeEmitter.lookupById(newEmployeeEmitter.data,1)});
employee.EmployeeEmitter.prototype.test= function () {
        this.emit('lookupById');
}
console.log(newEmployeeEmitter.test);

在我的employeeEmitter.js文件中：

var _ = require('underscore');
var EventEmitter = require('events').EventEmitter;
module.exports = {
    EmployeeEmitter: function (args) {
        this.data = args;
        EventEmitter.call(this);
    },
    lookupById : function(data,id){
        var foundId = _.where(data,{id:id});
        return foundId[0];
    },
    lookupByLastName : function(data,lastName) {
        return _.where(data,{lastName: lastName});
    },
    addEmployee: function (data, firstName, lastName) {
        // obtain next id
        var newId = function (data) {
            var id = _.max(data, function (data) {
                return data.id;
            });
            return id.id + 1;
        }
        // return new data (old data + new object, but without mutation of initial object)
        data.push( {id:newId(data), firstName: firstName, lastName: lastName });
        return data;
    }
}

我希望当我运行app.js时，控制台窗口中的输出应为：

{id：2，firstName：＆＃39; Jane＆＃39;，lastName：＆＃39; Smith＆＃39; }

然而，它显示[功能]。我不知道会发生什么。谁能帮我？非常感谢你！

Answer 1

您实际上没有调用测试功能，当您发出事件时，他们不会返回任何内容。

更像这样的东西可能有用：

var _ = require('underscore');
var employee = require('./employeeEmitter');
var EventEmitter = require('events').EventEmitter;
var emitter = new EventEmitter();
var inherits = require('util').inherits;
var data = [
    {id:1, firstName: 'John', lastName: 'Smith'},
    {id:2, firstName: 'Jane', lastName: 'Smith'},
    {id:3, firstName: 'John', lastName: 'Doe'}
];
inherits(employee.EmployeeEmitter, EventEmitter);
var newEmployeeEmitter = new employee.EmployeeEmitter(data);
newEmployeeEmitter.on('lookupById',function(){console.log(newEmployeeEmitter.lookupById(newEmployeeEmitter.data,1));});
employee.EmployeeEmitter.prototype.test= function () {
        this.emit('lookupById');
}
newEmployeeEmitter.test();

Node.js事件处理程序不起作用

1 个答案: