In this post, I will show you how to find the age of a person based on the birthdate. i.e. we will take the year, month and day of birth as input and print out the age.
- take the user birthdate as input
- Prints out the age.
Let’s take a look at the below program:
const userDOB = new Date("1989/11/17"); const today = new Date(); const msDiff = today - userDOB; const age = Math.floor(msDiff / (365.25*24*60*60*1000)) console.log(age)
If today is Nov, 17, 2020, it will print 31.
- Here, userDOB is the Date object of user date of birth.
- today is the Date object for current date.
- msDiff variable holds the difference of today and userDOB. This difference is in milliseconds.
- We are diving with the total milliseconds in a year to find out the age for the user whose date of birth is given.
365.25 - Total days in a year 24 - Hours in one day 60 - Mins in one hour 60 - seconds in one minute 1000 - Converting the second value to milliseconds.
Now, let me show you how it will look like if I use momentjs :
const userDOB = moment('1989/11/17', 'YYYY/M/D'); const age = moment().diff(userDOB, 'years') console.log(age)
Just one line of code to get the years difference. You can also find the difference in months, days etc.
moment.js is a lightweight library and I prefer to use it than the previous option.
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