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JavaScript: Calculate age

JavaScript Datetime: Exercise-18 with Solution

Write a JavaScript program to calculate age.

Test Data:
console.log(calculate_age(new Date(1982, 11, 4)));
35
console.log(calculate_age(new Date(1962, 1, 1)));
56

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript program to calculate age</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function calculate_age(dob) { 
    var diff_ms = Date.now() - dob.getTime();
    var age_dt = new Date(diff_ms); 
  
    return Math.abs(age_dt.getUTCFullYear() - 1970);
}

console.log(calculate_age(new Date(1982, 11, 4)));

console.log(calculate_age(new Date(1962, 1, 1)));

Sample Output:

35
56

Flowchart:

Flowchart: JavaScript- Calculate age

Live Demo:

See the Pen JavaScript - Calculate age-date-ex-18 by w3resource (@w3resource) on CodePen.


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Next: Write a JavaScript function to get the day of the month, 2 digits with leading zeros.

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JavaScript: Tips of the Day

Spread operator

const user = { name: 'Owen', age: 21 };
const admin = { admin: true, ...user };

console.log(admin);

It's possible to combine objects using the spread operator .... It lets you create copies of the key/value pairs of one object, and add them to another object. In this case, we create copies of the user object, and add them to the admin object. The admin object now contains the copied key/value pairs, which results in { admin: true, name: "Owen", age: 21 }.

Ref: https://bit.ly/323Y0P6