Check if a JavaScript string is a URL

Question

Is there a way in JavaScript to check if a string is a URL?

RegExes are excluded because the URL is most likely written like stackoverflow; that is to s

Answer 1

Improvement on the accepted answer...

• Check for ftp/ftps as protocol
• Has double escaping for backslashes (\\)
• Ensures that domains have a dot and an extension (.com .io .xyz)
• Allows full colon (:) in the path e.g. http://thingiverse.com/download:1894343
• Allows ampersand (&) in path e.g http://en.wikipedia.org/wiki/Procter_&_Gamble

• Allows @ symbol in path e.g. https://medium.com/@techytimo

  isURL(str) {
    var pattern = new RegExp('^((ft|htt)ps?:\\/\\/)?'+ // protocol
    '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|'+ // domain name and extension
    '((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address
    '(\\:\\d+)?'+ // port
    '(\\/[-a-z\\d%@_.~+&:]*)*'+ // path
    '(\\?[;&a-z\\d%@_.,~+&:=-]*)?'+ // query string
    '(\\#[-a-z\\d_]*)?$','i'); // fragment locator
    return pattern.test(str);
  }