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https://github.com/jonschlinkert/is-number

JavaScript/Node.js utility. Returns `true` if the value is a number or string number. Useful for checking regex match results, user input, parsed strings, etc.
https://github.com/jonschlinkert/is-number

float integer is isnan javascript jonschlinkert nan negative nodejs number numeric real zero

Last synced: 23 days ago
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JavaScript/Node.js utility. Returns `true` if the value is a number or string number. Useful for checking regex match results, user input, parsed strings, etc.

Host: GitHub
URL: https://github.com/jonschlinkert/is-number
Owner: jonschlinkert
License: mit
Created: 2014-09-22T03:40:34.000Z (about 10 years ago)
Default Branch: master
Last Pushed: 2022-09-15T14:46:56.000Z (about 2 years ago)
Last Synced: 2024-05-15T13:26:16.613Z (6 months ago)
Topics: float, integer, is, isnan, javascript, jonschlinkert, nan, negative, nodejs, number, numeric, real, zero
Language: JavaScript
Homepage: https://github.com/jonschlinkert
Size: 56.6 KB
Stars: 252
Watchers: 8
Forks: 48
Open Issues: 11
Metadata Files:
- Readme: README.md
- License: LICENSE

Awesome Lists containing this project

README

        # is-number [![NPM version](https://img.shields.io/npm/v/is-number.svg?style=flat)](https://www.npmjs.com/package/is-number) [![NPM monthly downloads](https://img.shields.io/npm/dm/is-number.svg?style=flat)](https://npmjs.org/package/is-number) [![NPM total downloads](https://img.shields.io/npm/dt/is-number.svg?style=flat)](https://npmjs.org/package/is-number) [![Linux Build Status](https://img.shields.io/travis/jonschlinkert/is-number.svg?style=flat&label=Travis)](https://travis-ci.org/jonschlinkert/is-number)

> Returns true if the value is a finite number.

Please consider following this project's author, [Jon Schlinkert](https://github.com/jonschlinkert), and consider starring the project to show your :heart: and support.

## Install

Install with [npm](https://www.npmjs.com/):

```sh

$ npm install --save is-number

```

## Why is this needed?

In JavaScript, it's not always as straightforward as it should be to reliably check if a value is a number. It's common for devs to use `+`, `-`, or `Number()` to cast a string value to a number (for example, when values are returned from user input, regex matches, parsers, etc). But there are many non-intuitive edge cases that yield unexpected results:

```js

console.log(+[]); //=> 0

console.log(+''); //=> 0

console.log(+'   '); //=> 0

console.log(typeof NaN); //=> 'number'

```

This library offers a performant way to smooth out edge cases like these.

## Usage

```js

const isNumber = require('is-number');

```

See the [tests](./test.js) for more examples.

### true

```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

Everything else is false, as you would expect:

```js

isNumber(Infinity);          // false

isNumber(NaN);               // false

isNumber(null);              // false

isNumber(undefined);         // false

isNumber('');                // false

isNumber('   ');             // false

isNumber('foo');             // false

isNumber([1]);               // false

isNumber([]);                // false

isNumber(function () {});    // false

isNumber({});                // false

```

## Release history

### 7.0.0

* Refactor. Now uses `.isFinite` if it exists.

* Performance is about the same as v6.0 when the value is a string or number. But it's now 3x-4x faster when the value is not a string or number.

### 6.0.0

* Optimizations, thanks to @benaadams.

### 5.0.0

**Breaking changes**

* removed support for `instanceof Number` and `instanceof String`

## Benchmarks

As with all benchmarks, take these with a grain of salt. See the [benchmarks](./benchmark/index.js) for more detail.

```

# all

v7.0 x 413,222 ops/sec ±2.02% (86 runs sampled)

v6.0 x 111,061 ops/sec ±1.29% (85 runs sampled)

parseFloat x 317,596 ops/sec ±1.36% (86 runs sampled)

fastest is 'v7.0'

# string

v7.0 x 3,054,496 ops/sec ±1.05% (89 runs sampled)

v6.0 x 2,957,781 ops/sec ±0.98% (88 runs sampled)

parseFloat x 3,071,060 ops/sec ±1.13% (88 runs sampled)

fastest is 'parseFloat,v7.0'

# number

v7.0 x 3,146,895 ops/sec ±0.89% (89 runs sampled)

v6.0 x 3,214,038 ops/sec ±1.07% (89 runs sampled)

parseFloat x 3,077,588 ops/sec ±1.07% (87 runs sampled)

fastest is 'v6.0'

```

## About

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).

Running Tests

Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:

```sh

$ npm install && npm test

```

Building docs

_(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_

To generate the readme, run the following command:

```sh

$ npm install -g verbose/verb#dev verb-generate-readme && verb

```

### Related projects

You might also be interested in these projects:

* [is-plain-object](https://www.npmjs.com/package/is-plain-object): Returns true if an object was created by the `Object` constructor. | [homepage](https://github.com/jonschlinkert/is-plain-object "Returns true if an object was created by the `Object` constructor.")

* [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. ")

* [isobject](https://www.npmjs.com/package/isobject): Returns true if the value is an object and not an array or null. | [homepage](https://github.com/jonschlinkert/isobject "Returns true if the value is an object and not an array or null.")

* [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.")

### Contributors

| **Commits** | **Contributor** | 

| --- | --- |

| 49 | [jonschlinkert](https://github.com/jonschlinkert) |

| 5 | [charlike-old](https://github.com/charlike-old) |

| 1 | [benaadams](https://github.com/benaadams) |

| 1 | [realityking](https://github.com/realityking) |

### Author

**Jon Schlinkert**

* [LinkedIn Profile](https://linkedin.com/in/jonschlinkert)

* [GitHub Profile](https://github.com/jonschlinkert)

* [Twitter Profile](https://twitter.com/jonschlinkert)

### License

Copyright © 2018, [Jon Schlinkert](https://github.com/jonschlinkert).

Released under the [MIT License](LICENSE).

***

_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on June 15, 2018._