JavaScript: Count the number of days passed since beginning of the year

Last update on April 24 2023 07:03:36 (UTC/GMT +8 hours)

JavaScript Datetime: Exercise-16 with Solution

Write a JavaScript function to count the number of days passed since the year began.

Test Data:
console.log(days_passed(new Date(2015, 0, 15)));
15
console.log(days_passed(new Date(2015, 11, 14)));
348

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to count the number of days passed since beginning of the year</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function days_passed(dt) {
  var current = new Date(dt.getTime());
  var previous = new Date(dt.getFullYear(), 0, 1);

  return Math.ceil((current - previous + 1) / 86400000);
}
console.log(days_passed(new Date(2015, 0, 15)));
console.log(days_passed(new Date(2015, 11, 14)));

Sample Output:

15
348

Flowchart:

Live Demo:

See the Pen JavaScript - Count the number of days passed since beginning of the year-date-ex- 16 by w3resource (@w3resource) on CodePen.

Improve this sample solution and post your code through Disqus

Previous: Write a JavaScript function to get the quarter (1 to 4) of the year.
Next: Write a JavaScript function to convert a Unix timestamp to time.