mirror of https://github.com/thangisme/notes.git
103 lines
3.4 KiB
Markdown
103 lines
3.4 KiB
Markdown
# is-number [](http://badge.fury.io/js/is-number) [](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._ |