爲什麼回調連接到一個被稱爲兩次的事件？

Question

我正在梳理this教程，我很好奇爲什麼這個回調被多次調用 - 在這種情況下是兩次。這裏是我的代碼：

'use strict'; 

var chai = require('chai'), 
    expect = chai.expect, 
    sinon = require('sinon'), 
    sinonChai = require('sinon-chai'); 

var Backbone = require('backbone'), 
    _ = require('lodash/dist/lodash.underscore'); 

chai.use(sinonChai); 

describe('Backbone.Events', function() { 
    var myObj; 

    beforeEach(function() { 
    myObj = {}; 
    _.extend(myObj, Backbone.Events); 
    }); 

    it('allows us to bind and trigger custom named events on an object', function() { 
    var callback = sinon.spy(); 

    myObj.bind('custom event', callback); 
    myObj.trigger('custom event'); 

    expect(callback).to.have.been.called;  // => passes 
    expect(callback).to.have.been.calledOnce; // => fails?? 
    expect(callback).to.have.been.calledTwice; // => passes, why? 
    }); 
}); 

任何見解？

Answer 1

您具有約束力，並觸發兩個事件custom eventcustom和event

嘗試將其更改爲custom_event