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