# 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) > Returns true if the value is a number. comprehensive tests. 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). ## Install Install with [npm](https://www.npmjs.com/) ```sh $ npm i is-number --save ``` ## Usage ```js var isNumber = require('is-number'); ``` ### true See the [tests](./test.js) for more examples. ```js isNumber(5e3) //=> 'true' isNumber(0xff) //=> 'true' isNumber(-1.1) //=> 'true' isNumber(0) //=> 'true' isNumber(1) //=> 'true' isNumber(1.1) //=> 'true' isNumber(10) //=> 'true' isNumber(10.10) //=> 'true' isNumber(100) //=> 'true' isNumber('-1.1') //=> 'true' isNumber('0') //=> 'true' isNumber('012') //=> 'true' isNumber('0xff') //=> 'true' isNumber('1') //=> 'true' isNumber('1.1') //=> 'true' isNumber('10') //=> 'true' isNumber('10.10') //=> 'true' isNumber('100') //=> 'true' isNumber('5e3') //=> 'true' isNumber(parseInt('012')) //=> 'true' isNumber(parseFloat('012')) //=> 'true' ``` ### False See the [tests](./test.js) for more examples. ```js isNumber('foo') //=> 'false' isNumber([1]) //=> 'false' isNumber([]) //=> 'false' isNumber(function () {}) //=> 'false' isNumber(Infinity) //=> 'false' isNumber(NaN) //=> 'false' isNumber(new Array('abc')) //=> 'false' isNumber(new Array(2)) //=> 'false' isNumber(new Buffer('abc')) //=> 'false' isNumber(null) //=> 'false' isNumber(undefined) //=> 'false' isNumber({abc: 'abc'}) //=> 'false' ``` ## Other projects * [even](https://www.npmjs.com/package/even): Get the even numbered items from an array. | [homepage](https://github.com/jonschlinkert/even) * [is-even](https://www.npmjs.com/package/is-even): Return true if the given number is even. | [homepage](https://github.com/jonschlinkert/is-even) * [is-odd](https://www.npmjs.com/package/is-odd): Returns true if the given number is odd. | [homepage](https://github.com/jonschlinkert/is-odd) * [is-primitive](https://www.npmjs.com/package/is-primitive): Returns `true` if the value is a primitive. | [homepage](https://github.com/jonschlinkert/is-primitive) * [kind-of](https://www.npmjs.com/package/kind-of): Get the native type of a value. | [homepage](https://github.com/jonschlinkert/kind-of) * [odd](https://www.npmjs.com/package/odd): Get the odd numbered items from an array. | [homepage](https://github.com/jonschlinkert/odd) ## Contributing Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](https://github.com/jonschlinkert/is-number/issues/new). ## Run tests Install dev dependencies: ```sh $ npm i -d && npm test ``` ## Author **Jon Schlinkert** + [github/jonschlinkert](https://github.com/jonschlinkert) + [twitter/jonschlinkert](http://twitter.com/jonschlinkert) ## License Copyright © 2015 Jon Schlinkert Released under the MIT license. *** _This file was generated by [verb-cli](https://github.com/assemble/verb-cli) on November 22, 2015._