factorial

returns the factorial of a number

Usage no npm install needed!

<script type="module">
  import factorial from 'https://cdn.skypack.dev/factorial';
</script>

README

Information

Packagefactorial
Description returns the factorial of a number

Usage

factorial(10) // 3628800
factorial(-10) // -3628800
factorial(0) // 1
factorial(21, {useBigInt: true}) // 51090942171709440000n

Factorials greater than 18!

When calculating factorials for numbers greater than 18 (or less than -18), you should set the second argument to an object with useBigInt set to true. This is because the result will start to exceed Javascript's MAX_SAFE_INTEGER value.

It is safe to set useBigInt for all values, even 18 and below, just make sure you handle the output appropriately as BigInt is not completely compatible with normal Ints.

LICENSE

(MIT License)

Copyright (c) 2013 Fractal contact@wearefractal.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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