Imagine you want to sort some German strings alphabetically. (Take this for example:)

const countries = [
  'Deutschland',
  'Ägypten',
  'Norwegen',
  'Albanien'
]

If you would sort them using Array.sort() method, you will get this result, which might not be what you want:

countries.sort()
// results in: ['Albanien', 'Deutschland', 'Norwegen', 'Ägypten']

But if you the .localeCompare method that is defined on any instance of String you can sort the string with a more locale aware algorithm. Try this:

countries.sort((a, b) => a.localeCompare(b))
// results in: ['Ägypten', 'Albanien', 'Deutschland', 'Norwegen']

The .localeCompare method takes even more options (in most browsers), to adjust its comparing algorithm. You can read all about it on the fabulous MDN documentation about it.