js check valid url code example

Example 1: url validator javascript

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

Example 2: javascript url check

const isAbsoluteUrl = url => /^[a-z][a-z0-9+.-]*:/.test(url);

// Example
isAbsoluteUrl('https://1loc.dev');          // true
isAbsoluteUrl('https://1loc.dev/foo/bar');  // true
isAbsoluteUrl('1loc.dev');                  // false
isAbsoluteUrl('//1loc.dev');

Example 3: javascript determine if string is valid url

function isValidHttpUrl(string) {
  let url;
  
  try {
    url = new URL(string);
  } catch (_) {
    return false;  
  }

  return url.protocol === "http:" || url.protocol === "https:";
}