PHP's strpos in TypeScript

How to use

Install via yarn add locutus and import: import { strpos } from 'locutus/php/strings/strpos'.

Or with CommonJS: const { strpos } = require('locutus/php/strings/strpos')

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	strpos('Kevin van Zonneveld', 'e', 5)	14

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

TSTypeScript JSJavaScript TSStandalone TS JSStandalone JS

Copy code

export function strpos(haystack: string, needle: string, offset: number): number | false {
  //      discuss at: https://locutus.io/php/strpos/
  // parity verified: PHP 8.3
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //     improved by: Onno Marsman (https://twitter.com/onnomarsman)
  //     improved by: Brett Zamir (https://brett-zamir.me)
  //     bugfixed by: Daniel Esteban
  //       example 1: strpos('Kevin van Zonneveld', 'e', 5)
  //       returns 1: 14

  const i = (haystack + '').indexOf(needle, offset || 0)
  return i === -1 ? false : i
}

export function strpos(haystack, needle, offset) {
  //      discuss at: https://locutus.io/php/strpos/
  // parity verified: PHP 8.3
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //     improved by: Onno Marsman (https://twitter.com/onnomarsman)
  //     improved by: Brett Zamir (https://brett-zamir.me)
  //     bugfixed by: Daniel Esteban
  //       example 1: strpos('Kevin van Zonneveld', 'e', 5)
  //       returns 1: 14

  const i = (haystack + '').indexOf(needle, offset || 0)
  return i === -1 ? false : i
}

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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