mplungjan mplungjan - 1 month ago 6
Javascript Question

Elegant method to generate array of random dates within two dates

I have a datepicker where I show two months and I want to randomly choose 3 dates in each visible month

$('.date').datepicker({
minDate: new Date(),
dateFormat: 'DD, MM, d, yy',
constrainInput: true,
beforeShowDay: processDates,
numberOfMonths: 2,
showButtonPanel: true,
showOn: "button",
buttonImage: "images/calendar_icon.jpg",
buttonImageOnly: true
});


Here is my calculation

var now = new Date();
var nowTime = parseInt(now.getTime()/1000);
var randomDateSet = {};

function getRandomSet(y,m) {
var monthIndex = "m"+y+""+m; // m20121 for Jan
if (randomDateSet[monthIndex]) return randomDateSet[monthIndex];
// generate here
.
. - I need this part
.
return randomDateSet[monthIndex];
}

function processDay(date) { // this is calculated for each day so we need a singleton for the array
var dateTime = parseInt(date.getTime()/1000);
if (dateTime <= (nowTime-86400)) {
return [false]; // earlier than today
}
var m = date.getMonth(), d = date.getDate(), y = date.getFullYear();
var randomDates = getRandomSet(y,m);

for (i = 0; i < randomDates.length; i++) {
if($.inArray((m+1) + '-' + d + '-' + y,randomDates) != -1 || new Date() > date) {
return [true,"highlight","Some message"];
}
}
return [true,"normal"]; // ordinary day
}

Answer

Maybe I am missing something, but isn't this it?

function randomDate(start, end) {
    return new Date(start.getTime() + Math.random() * (end.getTime() - start.getTime()));
}

randomDate(new Date(2012, 0, 1), new Date())
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