Javascript compare two dates to get a difference

1
votes

I am trying to compare two different dates to see if the date inputted is after 7 days of todays date. I have done a bit of googling and come up with this:

function val_date(input){
    var date = new Date(input);
    date = date.getTime() / 1000;
    var timestamp = new Date().getTime() + (7 * 24 * 60 * 60 * 1000)
    window.alert("Date: "+date + " = N_Date: "+timestamp);
    if(timestamp > date || timestamp === date){
        // The selected time is less than 7 days from now
        return false;
    }
    else if(timestamp < date){
    // The selected time is more than 7 days from now
        return true;
    }
    else{
    // -Exact- same timestamps.
        return false;
    }
}

I am using an alert so that I can check my progress to make sure the dates are different. The output of the alert just says:

Date: NaN = N_Date = 13255772630 (<- or something like that).

Is there something I am doing wrong here?
Not sure if it helps but my date format is DD-MM-YYYY

6
javascriptdatetimestampcompare
"...the alert just says: Date: NaN" This tells you that input, whatever it is, is a string that cannot be parsed by the Date constructor. The result of calling new Date("some invalid string") is a Date whose time number is NaN. - T.J. Crowder
what is value of input ? - Mithun Satheesh
What is your date format? - Praveen
my date format is DD-MM-YYYY - Paul Ledger

6 Answers

4
votes

If you are comparing dates and don't want to include time, you can use something like:

// dateString is format DD-MM-YYYY
function isMoreThan7DaysHence(dateString) {

    // Turn string into a date object at 00:00:00
    var t = dateString.split('-');
    var d0 = new Date(t[2], --t[1], t[0]);

    // Create a date for 7 days hence at 00:00:00
    var d1 = new Date();
    d1.setHours(0, 0, 0, 0);
    d1.setDate(d1.getDate() + 7);

    return d0 >= d1;
}

Note that the hours for today's date must be zeroed.

2
votes

Date: NaN Because string which you are passing to date creation is not possible to create Date

fiddle Demo

Date.prototype.addDays = function (days) {
    this.setDate(this.getDate() + days);
    return this;
};

function val_date(input) {
    var inputDate = new Date(input);
    var dateWeek = new Date().addDays(7);
    console.log(inputDate, dateWeek);
    if (inputDate < dateWeek) {
        // The selected time is less than 7 days from now
        return false;
    } else {
        // The selected time is more than 7 days from now
        return true;
    }
}
0
votes

Using moment.js:

moment([2013, 2, 29]).fromNow();
0
votes

This is pretty common and if you will be manipulating dates you might want to use a Javascript library for this. There is an excellent on called moment.js

Using this you would do something like:

moment().add('days', 7)

To find a week in the future.

0
votes

Assuming that input is a valid Javascript Date object, you could perhaps try: 

function dateDifference(oldDate) {
    var currentDate = new Date();
    var difference = currentDate - oldDate; //unit: milliseconds
    var numDays = 7;
    var threshHoldTime = numDays * (24 * 60 * 60 * 1000); //seven days in milliseconds
    if (difference > threshHoldTime ) {
        console.log("The difference is greateer then then 7 days");
    }
    else {
        console.log("the date is not enough: " + difference);
    }
}
0
votes

Try like this

var date = new Date(input).getTime(); // Get the milliseconds
var today = new Date();    

//You can't compare date, 
//so convert them to milliseconds
today = new Date(today.setDate(today.getDate() + 7)).getTime(); 
if (inputDate < today) {
    // The selected time is less than 7 days from now
    return false;
 } else if{ ()
    // -Exact- same timestamps.
    return false;
 }
 else {
    // The selected time is more than 7 days from now
    return true;
 }