如何使用GROUPBY在Backbone.js的分组集合？ [英] How to use groupBy in Backbone.js to group collections?

问题描述

一个例子集合（显示型号）：

An example collection (showing models only):

[
    {
        name: "Bob"
        date: "Thu Mar 29 2012"
    },
    {
        name: "James"
        date: "Fri Mar 30 2012"
    },
    {
        name: "Dylan"
        date: "Fri Mar 30 2012"
    },
    {
        name: "Stanley"
        date: "Sat Mar 31 2012"
    },
]

我

如何使用Underscore.js'GROUPBY功能组型号相同的日期？

How can I use Underscore.js' groupBy function to group models with the same date?

推荐答案

使用 _ GROUPBY（数据，'日期'）;

您也可以使用通过自定义的功能，但在这种情况下，没有必要为上述属性快捷语法正常工作。

You could also use pass a custom function, but in this case it's not necessary as the attribute shortcut syntax above works fine.

_.groupBy(data, function(row) {
    return row.date;
});

演示：

> _.groupBy(data, 'date')
{ 'Thu Mar 29 2012': [ { name: 'Bob', date: 'Thu Mar 29 2012' } ],
  'Fri Mar 30 2012':
   [ { name: 'James', date: 'Fri Mar 30 2012' },
     { name: 'Dylan', date: 'Fri Mar 30 2012' } ],
  'Sat Mar 31 2012': [ { name: 'Stanley', date: 'Sat Mar 31 2012' } ] }
> _.groupBy(data, function(row) { return row.date });
{ 'Thu Mar 29 2012': [ { name: 'Bob', date: 'Thu Mar 29 2012' } ],
  'Fri Mar 30 2012':
   [ { name: 'James', date: 'Fri Mar 30 2012' },
     { name: 'Dylan', date: 'Fri Mar 30 2012' } ],
  'Sat Mar 31 2012': [ { name: 'Stanley', date: 'Sat Mar 31 2012' } ] }
>

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