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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.
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
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.
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.
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.
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
var isNumber = require('is-number');
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'
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'
true
if the value is a primitive. | homepagePull requests and stars are always welcome. For bugs and feature requests, please create an issue.
Install dev dependencies:
$ npm i -d && npm test
Jon Schlinkert
Copyright © 2015 Jon Schlinkert Released under the MIT license.
This file was generated by verb-cli on November 22, 2015.
FAQs
Returns true if a number or string value is a finite number. Useful for regex matches, parsing, user input, etc.
The npm package is-number receives a total of 68,483,852 weekly downloads. As such, is-number popularity was classified as popular.
We found that is-number demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 3 open source maintainers collaborating on the project.
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