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115 lines
4.3 KiB
115 lines
4.3 KiB
4 years ago
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# is-number [](https://www.npmjs.com/package/is-number) [](https://npmjs.org/package/is-number) [](https://travis-ci.org/jonschlinkert/is-number)
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> Returns true if the value is a number. comprehensive tests.
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## Install
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Install with [npm](https://www.npmjs.com/):
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```sh
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$ npm install --save is-number
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```
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## Usage
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To understand some of the rationale behind the decisions made in this library (and to learn about some oddities of number evaluation in JavaScript), [see this gist](https://gist.github.com/jonschlinkert/e30c70c713da325d0e81).
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```js
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var isNumber = require('is-number');
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```
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### true
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See the [tests](./test.js) for more examples.
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```js
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isNumber(5e3) //=> 'true'
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isNumber(0xff) //=> 'true'
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isNumber(-1.1) //=> 'true'
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isNumber(0) //=> 'true'
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isNumber(1) //=> 'true'
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isNumber(1.1) //=> 'true'
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isNumber(10) //=> 'true'
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isNumber(10.10) //=> 'true'
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isNumber(100) //=> 'true'
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isNumber('-1.1') //=> 'true'
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isNumber('0') //=> 'true'
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isNumber('012') //=> 'true'
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isNumber('0xff') //=> 'true'
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isNumber('1') //=> 'true'
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isNumber('1.1') //=> 'true'
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isNumber('10') //=> 'true'
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isNumber('10.10') //=> 'true'
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isNumber('100') //=> 'true'
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isNumber('5e3') //=> 'true'
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isNumber(parseInt('012')) //=> 'true'
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isNumber(parseFloat('012')) //=> 'true'
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```
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### False
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See the [tests](./test.js) for more examples.
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```js
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isNumber('foo') //=> 'false'
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isNumber([1]) //=> 'false'
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isNumber([]) //=> 'false'
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isNumber(function () {}) //=> 'false'
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isNumber(Infinity) //=> 'false'
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isNumber(NaN) //=> 'false'
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isNumber(new Array('abc')) //=> 'false'
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isNumber(new Array(2)) //=> 'false'
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isNumber(new Buffer('abc')) //=> 'false'
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isNumber(null) //=> 'false'
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isNumber(undefined) //=> 'false'
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isNumber({abc: 'abc'}) //=> 'false'
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```
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## About
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### Related projects
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* [even](https://www.npmjs.com/package/even): Get the even numbered items from an array. | [homepage](https://github.com/jonschlinkert/even "Get the even numbered items from an array.")
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* [is-even](https://www.npmjs.com/package/is-even): Return true if the given number is even. | [homepage](https://github.com/jonschlinkert/is-even "Return true if the given number is even.")
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* [is-odd](https://www.npmjs.com/package/is-odd): Returns true if the given number is odd. | [homepage](https://github.com/jonschlinkert/is-odd "Returns true if the given number is odd.")
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* [is-primitive](https://www.npmjs.com/package/is-primitive): Returns `true` if the value is a primitive. | [homepage](https://github.com/jonschlinkert/is-primitive "Returns `true` if the value is a primitive. ")
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* [kind-of](https://www.npmjs.com/package/kind-of): Get the native type of a value. | [homepage](https://github.com/jonschlinkert/kind-of "Get the native type of a value.")
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* [odd](https://www.npmjs.com/package/odd): Get the odd numbered items from an array. | [homepage](https://github.com/jonschlinkert/odd "Get the odd numbered items from an array.")
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### Contributing
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Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
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### Building docs
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_(This document was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme) (a [verb](https://github.com/verbose/verb) generator), please don't edit the readme directly. Any changes to the readme must be made in [.verb.md](.verb.md).)_
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To generate the readme and API documentation with [verb](https://github.com/verbose/verb):
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```sh
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$ npm install -g verb verb-generate-readme && verb
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```
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### Running tests
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Install dev dependencies:
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```sh
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$ npm install -d && npm test
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```
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### Author
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**Jon Schlinkert**
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* [github/jonschlinkert](https://github.com/jonschlinkert)
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* [twitter/jonschlinkert](http://twitter.com/jonschlinkert)
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### License
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Copyright © 2016, [Jon Schlinkert](https://github.com/jonschlinkert).
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Released under the [MIT license](https://github.com/jonschlinkert/is-number/blob/master/LICENSE).
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***
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_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.1.30, on September 10, 2016._
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