JS Check if multiple dates are within range

Question

I have the following code where I have an arrival date and departure date and edit their format, as well as a disabled date:

var aankomstDatum = "19-05-2018";
var parts = aankomstDatum.split('-');
aankomstDatumDate = new Date(parts[2],parts[1]-1,parts[0]);

vertrekDatum = "02-06-2018";
var parts2 = vertrekDatum.split('-');
vertrekDatumDate = new Date(parts2[2],parts2[1]-1,parts2[0]);

var aankomstDatumDateCheck = (aankomstDatumDate.getMonth() + 1) + '/' + aankomstDatumDate.getDate() + '/' +  aankomstDatumDate.getFullYear();
//alert(aankomstDatumDateCheck);

var vertrekDatumDateCheck = (vertrekDatumDate.getMonth() + 1) + '/' + vertrekDatumDate.getDate() + '/' +  vertrekDatumDate.getFullYear();
//alert(vertrekDatumDateCheck);

var disabledDates = "26-05-2018";
var partsdisabled = disabledDates.split('-');
var disableddatesDatumDate = new Date(partsdisabled[2], partsdisabled[1]-1, partsdisabled[0]); //alert(disableddatesDatumDate);

var disableddatesDatumDateCheck = (disableddatesDatumDate.getMonth() + 1) + '/' + disableddatesDatumDate.getDate() + '/' +  disableddatesDatumDate.getFullYear();
//alert(disableddatesDatumDateCheck);

if(dateCheck(aankomstDatumDateCheck,vertrekDatumDateCheck,disableddatesDatumDateCheck)) {
    console.log("Not available");
} else {
    console.log("Available");
}

function dateCheck() {
    return true;
}

Basically, if the disabled date is between the arrival date and departure date, the if-else fires, and in the other case the else.

This code works (hooray!), but I'm not there yet. Because I planned to have multiple dates as var disabledDates and that's where I'm stuck. So, how can edit the code that multiple disabled dates are checked?

Answer 1

Here's a simplified version of your code, which works as you ask. I think it's better to construct Date objects using ISO8601 formatted text while testing i.e. "2018-05-19" (which creates dates in UTC). Also see tips at the end of the answer.

Click the Run code snippet button below the code to see the console output (much better than using alert):

var start = new Date("2018-05-19");
var end = new Date("2018-06-02");

var bookings = [
    new Date("2018-05-26"),
    new Date("2018-05-28")
];

if (validPeriod(start, end, bookings)) {
    console.log("no bookings found");
} else {
    console.log("found at least one booking");
}

function validPeriod(start, end, bookings) {
    var valid = true;

    for (var i = 0; i < bookings.length; i++) {
        var date = bookings[i];
        if (start <= date && date <= end) {
            valid = false;
            break;
        }
    }

    return valid;
}

Tips

I strongly recommend you use Moment.js to work with dates. It'll save you headaches in the future.

If you don't opt for Moment.js, just remember that depending on how you create the date will depend on which timezone is used, and depending on the timezone of your computer which date will display, One easy way is to use the new Date(year, month, day, hours, minutes, seconds) constructor:

// for a browser/computer in timezone GMT+0200 (Paris)

// create a local date
new Date(2018, 5-1, 18).toString() // "Fri May 18 2018 00:00:00 GMT+0200 (CEST)"
new Date(2018, 5-1, 18).toISOString() // "2018-05-17T22:00:00.000Z"

// create a UTC date
new Date(Date.UTC(2018, 5-1, 18)).toString() // "Fri May 18 2018 02:00:00 GMT+0200 (CEST)"
new Date(Date.UTC(2018, 5-1, 18)).toISOString() // "2018-05-18T00:00:00.000Z"

// for a browser/computer in timezone GMT-0400 (New York)

// create a local date
new Date(2018, 5-1, 18).toString() // "Fri May 18 2018 00:00:00 GMT-0400 (EDT)"
new Date(2018, 5-1, 18).toISOString() // "2018-05-18T04:00:00.000Z"

// create a UTC date
new Date(Date.UTC(2018, 5-1, 18)).toString() // "Thu May 17 2018 20:00:00 GMT-0400 (EDT)"
new Date(Date.UTC(2018, 5-1, 18)).toISOString() // "2018-05-18T00:00:00.000Z"

But watch out if you use a string for the Date constructor because it uses Date.parse(dateString) internally and sometimes it's interpreted as a local date, and sometimes UTC:

// for a browser/computer in timezone GMT-0400 (New York)
new Date("08-19-2018"); // Sun Aug 19 2018 00:00:00 GMT-0400 (EDT) <-- local
new Date("08/19/2018"); // Sun Aug 19 2018 00:00:00 GMT-0400 (EDT) <-- local
new Date("2018-05-19"); // Fri May 18 2018 20:00:00 GMT-0400 (EDT) <-- UTC
new Date("2018/05/19"); // Sat May 19 2018 00:00:00 GMT-0400 (EDT) <-- local

Answer 2

Adding to the @djdavemark's answer,

You can also use JavaScript's in build some function to check if any date is falling in the given range.

As @RobG mentioned that for some browsers these date strings might give wrong results, therefore just to be safe you can explicitly format in the way Date constructor accepts.

From @CMS's answer Question: Why does Date.parse give incorrect results?

function parseDate(input) {
  var parts = input.split('-');
  // new Date(year, month [, day [, hours[, minutes[, seconds[, ms]]]]])
  return new Date(parts[2], parts[1]-1, parts[0]); // Note: months are 0-based
}  

var startData = parseDate("19-05-2018")
var endDate = parseDate("25-05-2018")

var dateSet = [
"20-05-2018",
"21-05-2018",
"22-05-2018"
];

var dateSet2 = [
"26-05-2018",
];

function inBetween(element, index, array) {
  return parseDate(element) >= startData && parseDate(element) <= endDate;
}

console.log(dateSet.some(inBetween))

console.log(dateSet2.some(inBetween))

This looks more elegant.

For more information on array's some method MDN Docs