22 lines
670 B
Markdown
22 lines
670 B
Markdown
---
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title: dayOfYear
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tags: date,beginner
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firstSeen: 2018-09-29T13:22:20+03:00
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lastUpdated: 2020-10-19T18:51:03+03:00
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---
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Gets the day of the year (number in the range 1-366) from a `Date` object.
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- Use the `Date` constructor and `Date.prototype.getFullYear()` to get the first day of the year as a `Date` object.
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- Subtract the first day of the year from `date` and divide with the milliseconds in each day to get the result.
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- Use `Math.floor()` to appropriately round the resulting day count to an integer.
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```js
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const dayOfYear = date =>
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Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);
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```
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```js
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dayOfYear(new Date()); // 272
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```
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