Javascript Date Comparison
To check the equality of Date values:
var date1 = new Date();
var date2 = new Date(date1.valueOf() + 10);
console.log(date1.valueOf() === date2.valueOf());Output
Note that you must use valueOf() or getTime() to compare the values of Date objects because the equality operator will compare if two object references are the same. For example:
var date1 = new Date();
var date2 = new Date();
console.log(date1 === date2);Output
Whereas if the variables point to the same object:
var date1 = new Date();
var date2 = date1;
console.log(date1 === date2);Output
However, the other comparison operators will work as usual and you can use < and > to compare that one date is earlier or later than the other. For example:
var date1 = new Date();
var date2 = new Date(date1.valueOf() + 10);
console.log(date1 < date2);Output
It works even if the operator includes equality:
var date1 = new Date();
var date2 = new Date(date1.valueOf());
console.log(date1 <= date2);Output
Date Difference Calculation
To compare the difference of two dates, we can do the comparison based on the timestamp.
var date1 = new Date();
var date2 = new Date(date1.valueOf() + 5000);
var dateDiff = date1.valueOf() - date2.valueOf();
var dateDiffInYears = dateDiff/1000/60/60/24/365;
console.log("Date difference in years : " + dateDiffInYears);