Usage of Intl.Segmenter() breaks on Firefox #50
Description
3 weeks ago, #47 introduced Intl.Segmenter(). However, since it's not supported by Firefox, this will break sites using string-width@^6.0.0 (approx. 1500 installs).
For a real-world example, the error is shown as below when I visited this site over Firefox Nightly 115.0a1:
