PHP's strstr in TypeScript

How to use

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

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

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	strstr('Kevin van Zonneveld', 'van')	'van Zonneveld'
2	strstr('Kevin van Zonneveld', 'van', true)	'Kevin '
3	strstr('name@example.com', '@')	'@example.com'
4	strstr('name@example.com', '@', true)	'name'

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

TSTypeScript JSJavaScript TSStandalone TS JSStandalone JS

Copy code

export function strstr(haystack: string, needle: string, bool?: boolean): string | false {
  //      discuss at: https://locutus.io/php/strstr/
  // parity verified: PHP 8.3
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //     bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  //     improved by: Kevin van Zonneveld (https://kvz.io)
  //       example 1: strstr('Kevin van Zonneveld', 'van')
  //       returns 1: 'van Zonneveld'
  //       example 2: strstr('Kevin van Zonneveld', 'van', true)
  //       returns 2: 'Kevin '
  //       example 3: strstr('name@example.com', '@')
  //       returns 3: '@example.com'
  //       example 4: strstr('name@example.com', '@', true)
  //       returns 4: 'name'

  let pos = 0

  haystack += ''
  pos = haystack.indexOf(needle)
  if (pos === -1) {
    return false
  } else {
    if (bool) {
      return haystack.substr(0, pos)
    } else {
      return haystack.slice(pos)
    }
  }
}

export function strstr(haystack, needle, bool) {
  //      discuss at: https://locutus.io/php/strstr/
  // parity verified: PHP 8.3
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //     bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  //     improved by: Kevin van Zonneveld (https://kvz.io)
  //       example 1: strstr('Kevin van Zonneveld', 'van')
  //       returns 1: 'van Zonneveld'
  //       example 2: strstr('Kevin van Zonneveld', 'van', true)
  //       returns 2: 'Kevin '
  //       example 3: strstr('name@example.com', '@')
  //       returns 3: '@example.com'
  //       example 4: strstr('name@example.com', '@', true)
  //       returns 4: 'name'

  let pos = 0

  haystack += ''
  pos = haystack.indexOf(needle)
  if (pos === -1) {
    return false
  } else {
    if (bool) {
      return haystack.substr(0, pos)
    } else {
      return haystack.slice(pos)
    }
  }
}

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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