Events 主干js无法在上的事件中返回值
伙计们,我是backboneJs新手,我试着编写一个基本程序来返回events.on中的值,如下所示,但它不起作用Events 主干js无法在上的事件中返回值,events,backbone.js,Events,Backbone.js,伙计们,我是backboneJs新手,我试着编写一个基本程序来返回events.on中的值,如下所示,但它不起作用 $(function(){ // object.on(event, callback, [context])Alias: bind var object = {}; _.extend(object, Backbone.Events); object.on('add',function(a,b){ return a + b;
$(function(){
// object.on(event, callback, [context])Alias: bind
var object = {};
_.extend(object, Backbone.Events);
object.on('add',function(a,b){
return a + b;
});
var sum = object.trigger('add',1,3);
// not as I expected.
alert(sum);
});
我希望有人能给我一些想法,非常感谢。主干。创建事件不是为了返回值,而是作为对象的通知机制。将忽略已注册回调的返回值,并返回触发事件的实际对象(这就是sum不包含4的原因) 如果您确实需要从事件中提取某些内容,您可以按如下方式重新构造代码:
$(function(){
// object.on(event, callback, [context])Alias: bind
var object = {};
_.extend(object, Backbone.Events);
// register variable outside of callback scope
var sum;
object.on('add',function(a,b){
// store result inside variable coming from outside
sum = a + b;
});
// trigger don't return anything, but sum variable will be filled
object.trigger('add',1,3);
// not as I expected.
alert(sum);
});
关于这个问题,我提出了另一个解决方案,如下所示:
$(function(){
// object.on(event, callback, [context])Alias: bind
var object = {};
_.extend(object, Backbone.Events);
// add a attribute 'sum' for the object, to hold the value.
object.on('add',function(a,b){
return this.sum = a+b;
});
var r = object.trigger('add',1,3);
alert(r.sum);
});