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   1 # is-number [![NPM version](https://badge.fury.io/js/is-number.svg)](http://badge.fury.io/js/is-number)  [![Build Status](https://travis-ci.org/jonschlinkert/is-number.svg)](https://travis-ci.org/jonschlinkert/is-number)
   2
   3 > Returns true if the value is a number. comprehensive tests.
   4
   5 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).
   6
   7 ## Install
   8
   9 Install with [npm](https://www.npmjs.com/)
  10
  11 ```sh
  12 $ npm i is-number --save
  13 ```
  14
  15 ## Usage
  16
  17 ```js
  18 var isNumber = require('is-number');
  19 ```
  20
  21 ### true
  22
  23 See the [tests](./test.js) for more examples.
  24
  25 ```js
  26 isNumber(5e3)      //=> 'true'
  27 isNumber(0xff)     //=> 'true'
  28 isNumber(-1.1)     //=> 'true'
  29 isNumber(0)        //=> 'true'
  30 isNumber(1)        //=> 'true'
  31 isNumber(1.1)      //=> 'true'
  32 isNumber(10)       //=> 'true'
  33 isNumber(10.10)    //=> 'true'
  34 isNumber(100)      //=> 'true'
  35 isNumber('-1.1')   //=> 'true'
  36 isNumber('0')      //=> 'true'
  37 isNumber('012')    //=> 'true'
  38 isNumber('0xff')   //=> 'true'
  39 isNumber('1')      //=> 'true'
  40 isNumber('1.1')    //=> 'true'
  41 isNumber('10')     //=> 'true'
  42 isNumber('10.10')  //=> 'true'
  43 isNumber('100')    //=> 'true'
  44 isNumber('5e3')    //=> 'true'
  45 isNumber(parseInt('012'))   //=> 'true'
  46 isNumber(parseFloat('012')) //=> 'true'
  47 ```
  48
  49 ### False
  50
  51 See the [tests](./test.js) for more examples.
  52
  53 ```js
  54 isNumber('foo')             //=> 'false'
  55 isNumber([1])               //=> 'false'
  56 isNumber([])                //=> 'false'
  57 isNumber(function () {})    //=> 'false'
  58 isNumber(Infinity)          //=> 'false'
  59 isNumber(NaN)               //=> 'false'
  60 isNumber(new Array('abc'))  //=> 'false'
  61 isNumber(new Array(2))      //=> 'false'
  62 isNumber(new Buffer('abc')) //=> 'false'
  63 isNumber(null)              //=> 'false'
  64 isNumber(undefined)         //=> 'false'
  65 isNumber({abc: 'abc'})      //=> 'false'
  66 ```
  67
  68 ## Other projects
  69
  70 * [even](https://www.npmjs.com/package/even): Get the even numbered items from an array. | [homepage](https://github.com/jonschlinkert/even)
  71 * [is-even](https://www.npmjs.com/package/is-even): Return true if the given number is even. | [homepage](https://github.com/jonschlinkert/is-even)
  72 * [is-odd](https://www.npmjs.com/package/is-odd): Returns true if the given number is odd. | [homepage](https://github.com/jonschlinkert/is-odd)
  73 * [is-primitive](https://www.npmjs.com/package/is-primitive): Returns `true` if the value is a primitive.  | [homepage](https://github.com/jonschlinkert/is-primitive)
  74 * [kind-of](https://www.npmjs.com/package/kind-of): Get the native type of a value. | [homepage](https://github.com/jonschlinkert/kind-of)
  75 * [odd](https://www.npmjs.com/package/odd): Get the odd numbered items from an array. | [homepage](https://github.com/jonschlinkert/odd)
  76
  77 ## Contributing
  78
  79 Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](https://github.com/jonschlinkert/is-number/issues/new).
  80
  81 ## Run tests
  82
  83 Install dev dependencies:
  84
  85 ```sh
  86 $ npm i -d && npm test
  87 ```
  88
  89 ## Author
  90
  91 **Jon Schlinkert**
  92
  93 + [github/jonschlinkert](https://github.com/jonschlinkert)
  94 + [twitter/jonschlinkert](http://twitter.com/jonschlinkert)
  95
  96 ## License
  97
  98 Copyright © 2015 Jon Schlinkert
  99 Released under the MIT license.
 100
 101 ***
 102
 103 _This file was generated by [verb-cli](https://github.com/assemble/verb-cli) on November 22, 2015._