Array with object sorting with Underscore sortBy

问题:

I have this array. How do I use underscore '_.sortBy' to sort it according to start date?

[
    { 
        id: 'oljw832021kjnb389xzll323jk',
        start: { dateTime: '2013-09-26T13:30:00-07:00' },
        end: { dateTime: '2013-09-26T14:30:00-07:00' },
    },
    { 
        id: 'ed7l5tmckdp0lm90nvr4is3d4c',
        start: { dateTime: '2013-09-26T15:30:00-07:00' },
        end: { dateTime: '2013-09-26T16:30:00-07:00' },
    },
    { 
        id: 'etmasdsackdp0kjl0nvrkopioqw',
        start: { dateTime: '2013-09-26T18:00:00-07:00' },
        end: { dateTime: '2013-09-26T19:00:00-07:00' },
    }
]

回答1:

Use an iterator function, not a single string for a property:

_.sortBy(arr, function(o) { return o.start.dateTime; })

回答2:

I did it this way:

var sorted = _(list).sortBy(
                    function (item) {                        
                        return [new Date(item.effectiveDate).getTime(), item.batchId];
                    }), "batchId");

If you want it descending then it's the same thing but *-1

var sorted = _(list).sortBy(
                    function (item) {                        
                        return [new Date(item.effectiveDate).getTime()*-1, item.batchId];
                    }), "batchId");

In this example I am ordering by two fields, you can forget about the item.batchId.

Hope this helps someone.