Javascript Date Format After _.filter Lo-Dash Call

Question

Can anyone please help me with formatting a date after a lodash _.filter? The below code results in "Tue Jan 21 2014 00:00:00 GMT-0500 (Eastern Standard Time)". I'd like the date to be in "m/d/yy" format.

var testdata=[{"date": "1/21/2014", "y": 325, "z": 201, "a": 85},
                        {"date": "1/22/2014", "y": 250, "z": null, "a": 40},
                        {"date": "1/23/2014", "y": 125, "z": 500, "a": 60},
                        {"date": "1/24/2014", "y": 50, "z": 466, "a": 35}
                        ];

                    _.each(testdata, function(data){
                    var dateParts = data.date.split('/')
                    data.date = new Date(dateParts[2], dateParts[0] - 1, dateParts[1])
                    });

                    var startDate = new Date(start);
                    var endDate = new Date(end);

                    var requiredData = _.filter(testdata, function(data){
                        return data.date >= startDate && data.date <= endDate
                    }); 

Answer 1

You need to _.map() the _.filter()'ed array to format your dates accordingly.

Change your last line to:

var requiredData = _.map(
    _.filter(testdata, function(data){
        return data.date >= startDate && data.date <= endDate
    }), function(nextData){ 
        return nextData.date.getDate() + '/' + (nextData.date.getMonth()+1) + '/' + nextData.date.getFullYear().toString().split('').slice(2,4).join('');
    }
);

EDIT: I thought that you wanted only the formatted date. My bad. Change your requireData assignment to:

var requiredData = _.map(_.filter(testdata, function(data){
            return data.date >= startDate && data.date <= endDate
        } // end of _.filter()'s handler function
    ),
    function(nextData){
        // create new field called 'formatted' in each object with formatted date
        nextData.formatted = (nextData.date.getMonth()+1) + '/' + nextData.date.getDate() + '/' + nextData.date.getFullYear().toString().split('').slice(2,4).join(''); 
        return nextData; 
    } // end of _.map()'s handler function
);

This will make requiredData an array of object as you had originally with the addition that each one will have a property formatted that will hold the date in format m/d/yy