@toolbuilder/isnumber NPM

IsNumber

Well tested 'is number' checks, that can accept number-like strings, and non-finite values as desired.

There are a lot of is number tests out there. Many of them don't work quite right. Others use a different definition of is number than you might want. So after spending way too much time for such a simple thing, here are four checks:

Function	number literals	number-like strings	Infinity and NaN	Infinity and NaN strings	other strings
isNumeric	true	true	true	true	false
isNumber	true	false	true	false	false
isFiniteNumeric	true	true	false	false	false
isFiniteNumber	true	false	false	false	false

Installation

npm install --save @toolbuilder/isnumber

Getting Started

This is a dual package, so named exports are available for both CommonJS and ES modules.

import { isNumeric, isFiniteNumeric, isNumber, isFiniteNumber } from '@toolbuilder/isnumber'

console.log(isNumeric('1.234')) // true because it looks like a number
console.log(isFiniteNumeric(42.54)) // true
console.log(isNumber('1.234')) // false because it is a string
console.log(isFiniteNumber(-Infinity)) // false

API

API documentation follows.

isNumber

Test if n is a number.

Includes Infinities and NaN, does not include strings that look like numbers

Parameters:

n any value to test

isNumber(1.23) // true
isNumber(Infinity) // true
isNumber(NaN) // true
isNumber('1.23') // false

Returns boolean true if is number, false otherwise

isNumeric

Test if n is a number, or string that parses to a number. Includes infinities and NaN.

Non-finite strings are: 'Infinity', '-Infinity', and 'NaN'.

Parameters:

n any value to test

isNumeric(1.23) // true
isNumeric('Infinity') // true
isNumeric(NaN) // true
isNumeric('1.23') // true
isNumeric('hi') // false

Returns boolean true if is numeric, false otherwise

isFiniteNumber

Test if n is a finite number.

Does not include infinities, NaN, or strings that look like numbers.

Parameters:

n any value to test

isFiniteNumber(1.23) // true
isFiniteNumber(Infinity) // false
isFiniteNumber(NaN) // false
isFiniteNumber('1.23') // false

Returns boolean true if is a finite number, false otherwise

isFiniteNumeric

Test if n is a finite number, or string that parses to a finite number.

Does not include infinities, NaN

Parameters:

n any value to test

isFiniteNumeric(1.23) // true
isFiniteNumeric('Infinity') // false
isFiniteNumeric(NaN) // false
isFiniteNumeric('1.23') // true
isFiniteNumeric('hi') // false

Returns boolean true if is a finite number, false otherwise

Credits

The isFiniteNumeric implementation, and the most of the tests were copied from this site. I found these tests on Stack Overflow in an answer by 'CMS'. Thanks!

Contributing

Contributions are welcome. Please create a pull request.

I use pnpm instead of npm.
Run the unit tests with pnpm test
Package verification requires pnpm to be installed globally.
- npm install -g pnpm
- pnpm install
- pnpm build to build cjs, docs, and *.d.ts
- pnpm run check:packfile to test against ES and CommonJS projects, as well as Electron
- pnpm run check to validate the package is ready for commit