Elegant method to generate array of random dates within two dates
JavascriptDateRandomJquery Ui-DatepickerJavascript Problem Overview
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
}
Javascript Solutions
Solution 1 - Javascript
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()));
}
const d = randomDate(new Date(2012, 0, 1), new Date());
console.log(d);
Solution 2 - Javascript
new Date(+(new Date()) - Math.floor(Math.random()*10000000000))
Solution 3 - Javascript
> Using Moment.js && @Demven Weir's answer to get a string value like "03/02/1975".
moment(new Date(+(new Date()) - Math.floor(Math.random()*10000000000)))
.format('MM/DD/YYYY');
NOTE: Keep adding a zero at a time to increase the span of years produced.
Solution 4 - Javascript
You can convert the boundary dates to integers (Date.getTime()
) and then use Math.random()
to generate your random dates within given boundaries. Then go back to Date
objects with Date.setTime()
.
Solution 5 - Javascript
function generateRandomDate() {
return new Date(+(new Date()) - Math.floor(Math.random() * 10000000000));
}
(new generateRandomDate()).toLocaleDateString('en-US')
You will get a random date in US format 4/25/2021
See this Demo on jsfiddle
Solution 6 - Javascript
You can use this snippet to get random date and format;
const emptyDate = new Date();
const randomDate = new Date();
const dateFormatter = Intl.DateTimeFormat('sv-SE');
const formattedRandomDate = dateFormatter.format(emptyDate.setDate(randomDate.getDate() - Math.floor(Math.random()*1000)));
Solution 7 - Javascript
From examples in date-fns
const result = eachDayOfInterval({
start: new Date(2014, 9, 6),
end: new Date(2014, 9, 10)
})