PHP's is_numeric in TypeScript

How to use

Install via yarn add locutus and import: import { is_numeric } from 'locutus/php/var/is_numeric'.

Or with CommonJS: const { is_numeric } = require('locutus/php/var/is_numeric')

Use a bundler that supports tree-shaking so you only ship the functions you actually use. Vite, webpack, Rollup, and Parcel all handle this. For server-side use this is less of a concern.

Examples

These examples are extracted from test cases that automatically verify our functions against their native counterparts.

#	code	expected result
1	is_numeric(186.31)	true
2	is_numeric('Kevin van Zonneveld')	false
3	is_numeric(' +186.31e2')	true
4	is_numeric('')	false
5	is_numeric([])	false
6	is_numeric('1 ')	false

Here's what our current TypeScript equivalent to PHP's is_numeric looks like.

TSTypeScript JSJavaScript TSStandalone TS JSStandalone JS

Copy code

import type { PhpRuntimeValue } from '../_helpers/_phpTypes.ts'

type NumericValue = PhpRuntimeValue

export function is_numeric(mixedVar: NumericValue): mixedVar is number | string {
  //  discuss at: https://locutus.io/php/is_numeric/
  // original by: Kevin van Zonneveld (https://kvz.io)
  // improved by: David
  // improved by: taith
  // bugfixed by: Tim de Koning
  // bugfixed by: WebDevHobo (https://webdevhobo.blogspot.com/)
  // bugfixed by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: Denis Chenu (https://shnoulle.net)
  //   example 1: is_numeric(186.31)
  //   returns 1: true
  //   example 2: is_numeric('Kevin van Zonneveld')
  //   returns 2: false
  //   example 3: is_numeric(' +186.31e2')
  //   returns 3: true
  //   example 4: is_numeric('')
  //   returns 4: false
  //   example 5: is_numeric([])
  //   returns 5: false
  //   example 6: is_numeric('1 ')
  //   returns 6: false

  const whitespace = [
    ' ',
    '\n',
    '\r',
    '\t',
    '\f',
    '\x0b',
    '\xa0',
    '\u2000',
    '\u2001',
    '\u2002',
    '\u2003',
    '\u2004',
    '\u2005',
    '\u2006',
    '\u2007',
    '\u2008',
    '\u2009',
    '\u200a',
    '\u200b',
    '\u2028',
    '\u2029',
    '\u3000',
  ].join('')

  // @todo: Break this up using many single conditions with early returns
  if (typeof mixedVar === 'number') {
    return !Number.isNaN(mixedVar)
  }

  if (typeof mixedVar !== 'string') {
    return false
  }

  return mixedVar !== '' && whitespace.indexOf(mixedVar.slice(-1)) === -1 && !Number.isNaN(Number(mixedVar))
}

export function is_numeric(mixedVar) {
  //  discuss at: https://locutus.io/php/is_numeric/
  // original by: Kevin van Zonneveld (https://kvz.io)
  // improved by: David
  // improved by: taith
  // bugfixed by: Tim de Koning
  // bugfixed by: WebDevHobo (https://webdevhobo.blogspot.com/)
  // bugfixed by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: Denis Chenu (https://shnoulle.net)
  //   example 1: is_numeric(186.31)
  //   returns 1: true
  //   example 2: is_numeric('Kevin van Zonneveld')
  //   returns 2: false
  //   example 3: is_numeric(' +186.31e2')
  //   returns 3: true
  //   example 4: is_numeric('')
  //   returns 4: false
  //   example 5: is_numeric([])
  //   returns 5: false
  //   example 6: is_numeric('1 ')
  //   returns 6: false

  const whitespace = [
    ' ',
    '\n',
    '\r',
    '\t',
    '\f',
    '\x0b',
    '\xa0',
    '\u2000',
    '\u2001',
    '\u2002',
    '\u2003',
    '\u2004',
    '\u2005',
    '\u2006',
    '\u2007',
    '\u2008',
    '\u2009',
    '\u200a',
    '\u200b',
    '\u2028',
    '\u2029',
    '\u3000',
  ].join('')

  // @todo: Break this up using many single conditions with early returns
  if (typeof mixedVar === 'number') {
    return !Number.isNaN(mixedVar)
  }

  if (typeof mixedVar !== 'string') {
    return false
  }

  return mixedVar !== '' && whitespace.indexOf(mixedVar.slice(-1)) === -1 && !Number.isNaN(Number(mixedVar))
}

Improve this function

Locutus is a community effort following The McDonald's Theory: we ship first iterations, hoping others will improve them. If you see something that could be better, we'd love your contribution.

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