spell-out-numbers.php

<?php

Str::macro('spellOutNumbers', static function($value, $locale = 'en_us') {
  $separatorFormatter = new \NumberFormatter($locale, \NumberFormatter::DECIMAL);
  $groupingSeparator = preg_quote($separatorFormatter->getSymbol(\NumberFormatter::GROUPING_SEPARATOR_SYMBOL), '/');
  $decimalSeparator = preg_quote($separatorFormatter->getSymbol(\NumberFormatter::DECIMAL_SEPARATOR_SYMBOL), '/');
  
  $spellOutFormatter = new \NumberFormatter($locale, \NumberFormatter::SPELLOUT);
  
  return preg_replace_callback(
    "/((?:\d+$groupingSeparator)*\d+(?:$decimalSeparator\d+)?)/",
    static fn($match) => $spellOutFormatter->format(preg_replace("/$groupingSeparator/", '', $match[0])),
    $value
  );
});