is-number

What is is-number?

The is-number npm package is a simple utility for checking if a value is a number. It works with various types of numeric representations, including strings that can be coerced to numbers, and provides a straightforward API for determining if a value can be considered a number in JavaScript.

What are is-number's main functionalities?

Check if a value is a number

This feature allows you to check if a value is a number, including numeric strings.

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

console.log(isNumber(5)); // true
console.log(isNumber('5')); // true
console.log(isNumber('five')); // false

Check if a value is not a number

This feature allows you to check if a value is not a number, including strings that cannot be coerced to numbers and other non-numeric types.

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

console.log(isNumber('foo')); // false
console.log(isNumber([1, 2, 3])); // false

Check if a value is a finite number

This feature allows you to check if a value is a finite number, excluding Infinity, -Infinity, and NaN.

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

console.log(isNumber(Infinity)); // false
console.log(isNumber(-Infinity)); // false
console.log(isNumber(NaN)); // false

Other packages similar to is-number

isnumeric

The isnumeric package offers similar functionality to is-number by checking if a value is numeric. It is similar in its simplicity and direct approach.

numerable

The numerable package is a more comprehensive library for number validation and formatting. It provides additional functionality compared to is-number, such as parsing and formatting numbers with localization support.

validate.io-number-primitive

This package is part of the validate.io suite and checks if a value is a number primitive. It is more strict than is-number as it does not consider numeric strings to be numbers.

README

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.

Install with npm

npm i is-number --save

Usage

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

true

See the tests for more examples.

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 for more examples.

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

• kind-of: Get the native type of a value.
• is-primitive: Returns true if the value is a primitive.
• even: Get the even numbered items from an array.
• odd: Get the odd numbered items from an array.
• is-even: Return true if the given number is even.
• is-odd: Returns true if the given number is odd.

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue

Run tests

Install dev dependencies.

npm i -d && npm test

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright (c) 2015 Jon Schlinkert
Released under the MIT license

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This file was generated by verb-cli on March 05, 2015.