Slugify support for international characters

[kmturley]

[ ] bug report
[x] feature request

Current behavior
I am trying to slugify a city name: Malmö
{{ 'Malmö' | slugify }} = malm

Expected behavior
I would expect it to replace the ö for an o
{{ 'Malmö' | slugify }} = malmo

Minimal reproduction of the problem with instructions
plnkr isn't loading right now, but simple to replicate. I have previously been using a function which does the replacement for you:

slugify(text) {
    if (text) {
      const specialChars = {'à': 'a', 'ä': 'a', 'á': 'a', 'â': 'a', 'æ': 'a', 'å': 'a', 'ë': 'e', 'è': 'e', 'é': 'e',
      'ê': 'e', 'î': 'i', 'ï': 'i', 'ì': 'i', 'í': 'i', 'ò': 'o', 'ó': 'o', 'ö': 'o', 'ô': 'o', 'ø': 'o', 'ù': 'o',
      'ú': 'u', 'ü': 'u', 'û': 'u', 'ñ': 'n', 'ç': 'c', 'ß': 's', 'ÿ': 'y', 'œ': 'o', 'ŕ': 'r', 'ś': 's', 'ń': 'n',
      'ṕ': 'p', 'ẃ': 'w', 'ǵ': 'g', 'ǹ': 'n', 'ḿ': 'm', 'ǘ': 'u', 'ẍ': 'x', 'ź': 'z', 'ḧ': 'h', '·': '-', '/': '-',
      '_': '-', ', ': '-', ': ': '-', ';': '-'};

      return text.toString().toLowerCase()
        .replace(/\s+/g, '-')           // Replace spaces with -
        .replace(/./g, (target, index, str) => specialChars[target] || target) // Replace special characters using the hash map
        .replace(/&/g, '-and-')         // Replace & with 'and'
        .replace(/[^\w\-]+/g, '')       // Remove all non-word chars
        .replace(/\-\-+/g, '-')         // Replace multiple - with single -
        .replace(/^-+/, '')             // Trim - from start of text
        .replace(/-+$/, '');             // Trim - from end of text
    } else {
      return false;
    }
  }

What is the motivation / use case for changing the behavior?
nicer slugs for urls, easier to read as they are closer to the originals