PHP's substr_count in JavaScript

How to use

You you can install via yarn add locutus and require this function via const substr_count = require('locutus/php/strings/substr_count').

It is important to use a bundler that supports tree-shaking so that you only ship the functions that you actually use to your browser, instead of all of Locutus, which is massive. Examples are: Parcel, webpack, or rollup.js. For server-side use this is typically less of a concern.

Examples

Please note that these examples are distilled from test cases that automatically verify our functions still work correctly. This could explain some quirky ones.

#	code	expected result
1	substr_count('Kevin van Zonneveld', 'e')	3
2	substr_count('Kevin van Zonneveld', 'K', 1)	0
3	substr_count('Kevin van Zonneveld', 'Z', 0, 10)	false

Here’s what our current JavaScript equivalent to PHP's substr_count looks like.

module.exports = function substr_count(haystack, needle, offset, length) {
  //  discuss at: https://locutus.io/php/substr_count/
  // original by: Kevin van Zonneveld (https://kvz.io)
  // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  // improved by: Brett Zamir (https://brett-zamir.me)
  // improved by: Thomas
  //   example 1: substr_count('Kevin van Zonneveld', 'e')
  //   returns 1: 3
  //   example 2: substr_count('Kevin van Zonneveld', 'K', 1)
  //   returns 2: 0
  //   example 3: substr_count('Kevin van Zonneveld', 'Z', 0, 10)
  //   returns 3: false

  let cnt = 0

  haystack += ''
  needle += ''
  if (isNaN(offset)) {
    offset = 0
  }
  if (isNaN(length)) {
    length = 0
  }
  if (needle.length === 0) {
    return false
  }
  offset--

  while ((offset = haystack.indexOf(needle, offset + 1)) !== -1) {
    if (length > 0 && offset + needle.length > length) {
      return false
    }
    cnt++
  }

  return cnt
}

A community effort

Not unlike Wikipedia, Locutus is an ongoing community effort. Our philosophy follows The McDonald’s Theory. This means that we assimilate first iterations with imperfections, hoping for others to take issue with-and improve them. This unorthodox approach has worked very well to foster fun and fruitful collaboration, but please be reminded to use our creations at your own risk. THE SOFTWARE IS PROVIDED "AS IS" has never been more true than for Locutus.

Now go and: [ View on GitHub | Edit on GitHub | View Raw ]

---

« More PHP strings functions

Star