按照JavaScript中的多个规则对对象数组进行排序

Question

So I have an array of objects, and I would like to sort them following these two rules (in order of priority):

1. The numbers must be in numerical order
2. The times must be in chronological order

So, I want the objects not only to be sorted by numbers, but to be also be sorted by time. For example, this would be ok.

• 005: 2am
• 005: 3am
• 005: 4am
• 006: 2am
• 006: 3am

This is the structure of the part of the objects that interests us:

var notSortedData = {
                        number: number, // it's a string
                        scheduled_date: scheduled_date, // the format is "YYYY-MM-DD HH:MM:SS"
                    }

                    sortedTrains.push(notSortedData);

So, notSortedData is pushed in sortedTrains via a for loop. Then I do this, but it is not enough (as it doesn't respect my second condition):

// sorts all the numbers numerically
        sortedTrains.sort(function(a, b) {
            return parseInt(a.number) - parseInt(b.number);
        });

What do I need to do to make sure that my second condition is also respected? Thanks!

Answer 1

You can try this:

sortedTrains.sort(function(a, b) {
    // We parse the numbers
    var num1 = parseInt(a.number), num2 = parseInt(b.number);
    if (num1 != num2) return num1 - num2; // Return the difference IF they are not equal
    var date1 = new Date(a.scheduled_date), date2 = new Date(b.scheduled_date);
    // We only get here if the numbers are equal
    return date1 - date2;
});

Answer 2

I would suggest to utilize a library such as underscore or lo-Dash, because later you might add more sort conditions or change them and using the library will greatly reduce the noisiness of your code and save you development effort. Assuming lo-Dash is used, the code will be as elegant as follows:

var sortedTrains = [
  { 'number': 5,  'scheduled_date': '2014-10-12 00:00:00'},
  { 'number': 5,  'scheduled_date': '2014-10-12 01:00:00' },
  { 'number': 5,  'scheduled_date': '2014-10-12 02:00:00'},
  { 'number': 6,  'scheduled_date': '2014-10-12 03:00:00' }
];

var result = _.sortBy(sortedTrains, ['number', 'scheduled_date']);