Turns out what I call permalink is actually called Slug, permalink is the full URL and slug is “the part of a URL that identifies a page in human-readable keywords” you can read more about on Wikipedia’s Clean URL / Slug article and Wikipedia’s Permalink article.

Below is the function I used to Slugify blog titles, got it from Matt Hagemann, this is the link to the gist.

function slugify(string) {
  const a = 'àáâäæãåāăąçćčđďèéêëēėęěğǵḧîïíīįìłḿñńǹňôöòóœøōõṕŕřßśšşșťțûüùúūǘůűųẃẍÿýžźż·/_,:;'
  const b = 'aaaaaaaaaacccddeeeeeeeegghiiiiiilmnnnnooooooooprrsssssttuuuuuuuuuwxyyzzz------'
  const p = new RegExp(a.split('').join('|'), 'g')

  return string.toString().toLowerCase()
    .replace(/\s+/g, '-') // Replace spaces with -
    .replace(p, c => b.charAt(a.indexOf(c))) // Replace special characters
    .replace(/&/g, '-and-') // Replace & with 'and'
    .replace(/[^\w\-]+/g, '') // Remove all non-word characters
    .replace(/\-\-+/g, '-') // Replace multiple - with single -
    .replace(/^-+/, '') // Trim - from start of text
    .replace(/-+$/, '') // Trim - from end of text
}