### dayOfYear

Gets the day of the year from a `Date` object.

Use `new Date()` and `Date.prototype.getFullYear()` to get the first day of the year as a `Date` object, subtract it from the provided `date` and divide with the milliseconds in each day to get the result.
Use `Math.floor()` to appropriately round the resulting day count to an integer.

```js
const dayOfYear = date =>
  Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);
```

```js
dayOfYear(new Date()); // 272
```