/src/php/strings/stristr.js

module.exports = function stristr (haystack, needle, bool) {
  //  discuss at: http://locutus.io/php/stristr/
  // original by: Kevin van Zonneveld (http://kvz.io)
  // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  //   example 1: stristr('Kevin van Zonneveld', 'Van')
  //   returns 1: 'van Zonneveld'
  //   example 2: stristr('Kevin van Zonneveld', 'VAN', true)
  //   returns 2: 'Kevin '

  var pos = 0

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