# dayOfYear
> Determine the day of the year.
## Usage
```javascript
var dayOfYear = require( '@stdlib/time/day-of-year' );
```
#### dayOfYear( \[month\[, day, year]] )
Returns the day of the year.
```javascript
var num = dayOfYear();
// returns
```
By default, the function returns the day of the year for the current date (according to local time). To determine the day of the year for a particular day, provide `month`, `day`, and `year` arguments.
```javascript
var num = dayOfYear( 12, 31, 2016 );
// returns 366
num = dayOfYear( 12, 31, 2017 );
// returns 365
```
A `month` may be either a month's integer value, three letter abbreviation, or full name (case insensitive).
```javascript
var num = dayOfYear( 12, 31, 2016 );
// returns 366
num = dayOfYear( 'dec', 31, 2016 );
// returns 366
num = dayOfYear( 'december', 31, 2016 );
// returns 366
```
The function also supports providing a [`Date`][date-object] object.
```javascript
var num = dayOfYear( new Date() );
// returns
```
## Examples
```javascript
var dayOfYear = require( '@stdlib/time/day-of-year' );
var v;
var i;
for ( i = 0; i < 2021; i++ ) {
v = dayOfYear( 'Dec', 31, i );
console.log( 'In the year %d, December 31 is day number %d.', i, v );
}
```
* * *
## CLI
### Usage
```text
Usage: day-of-year [options] [ ]
Options:
-h, --help Print this message.
-V, --version Print the package version.
```
### Examples
```bash
$ day-of-year
```
For a specific date,
```bash
$ day-of-year 12 31 2016
366
```
[date-object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date