我正在尝试在Ember.js中实现“分组依据”功能,并且证明比我原先想象的更难.
[{date: '2014-01-15T16:22:16-08:00',message: 'Tidal wave occurred'},{date: '2014-01-15T05:00:16-08:00',message: 'Tornado destroyed town'},{date: '2014-01-13T14:22:16-08:00',message: 'Volcanic eruption,likely'},{date: '2014-01-13T16:24:16-08:00',message: 'Ice shelf calving off completely'},{date: '2014-01-11T11:27:26-08:00',message: 'Mother-in-law visiting'}]
我正在寻找类似于此的最终输出：
Today ---------- 4:22 pm - Tidal wave occurred 5:00 am - Tornado destroyed town Monday ---------- 2:22 pm - Volcanic eruption,likely ...etc.,etc.
现在这个数据绑定到ArrayController.每个对象都有一个计算属性,以获得分组比较的“年/月/日”.
var ActivityController = Em.ArrayController.extend({
groupedResults: function () {
var result = [];
//Iterate over each item in the list,but do what with it?
this.get('content').filter(function (item) {
});
return result;
}.property('content.[]')
});
解决方法
这是一个我已经改编了一下的Groupable实现：
Groupable = Ember.Mixin.create
group: null
ungroupedContent: null
groupedContent: (->
model = @
groupedContent = Ember.A([])
groupCallback = @get('group')
ungroupedContent = @get('ungroupedContent')
return groupedContent unless groupCallback
return groupedContent unless ungroupedContent
ungroupedContent.forEach (item) ->
group = groupCallback.call(model,item)
return unless groupKey = group.get('key')
foundGroup = groupedContent.findProperty('group.key',groupKey)
unless foundGroup
foundGroup = groupedContent.pushObject Ember.ArrayProxy.create
group: group,content: Ember.A([])
foundGroup.get('content').pushObject(item)
groupedContent
).property('group','ungroupedContent.@each')
控制器用法：
ActivitiesController = Ember.ArrayController.extend Groupable,ungroupedContentBinding: 'content' # tell Groupable where your default content is
# the callback that will be called for every
# item in your content array -
# just return the same 'key' to put it in the same group
group: (activity) ->
Ember.Object.create
key: moment.utc(activity.get('date')).format('YYYY-MM-DD') # using momentjs to pluck the day from the date
description: 'some string describing this group (if you want)'
模板用法：
{{#each groupedContent}}
{{group.key}} - {{group.description}}
{{#each content}}
Here's the really bad thing that happened: {{message}}
{{/each}}
{{/each}}
基本上,Groupable mixin所做的就是遍历普通内容ArrayProxy并调用一个函数来确定它属于哪个组.如果该组对象尚不存在(即未找到匹配的group.key),则在将当前内容项添加到组的内容之前创建它.
因此,您在模板中最终得到的是一个新的对象数组(ArrayProxy)(Ember.Object),每个对象都有一个group属性(必须至少具有一个用于标识它的键属性)和一个content属性(包含属于该组的内容).
