@toolbuilder/isnumber
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0.1.6 • Public • Published

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

Table of Contents

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

Issues

This project uses Github issues.

License

MIT

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npm i @toolbuilder/isnumber

Weekly Downloads

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Version

0.1.6

License

MIT

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  • toolbuilder