JS - Ensure valid web url - Prepend url scheme if necessary

js_url.md

JS - URL

getParameterByName

• https://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript/901144#901144

Ensure valid web url - Prepend url scheme if necessary

// Prepends "http://" to a URL that doesn't already contain "http://"
const prependUrlScheme = url => {
  // https://stackoverflow.com/a/3543261/3837223
  if (!/^https?:\/\//i.test(url)) {
    return 'http://' + url;
  }

  return url;
};

const hasTopLevelDomain = url => {
  // https://stackoverflow.com/a/34695026/3837223
  const parser = document.createElement('a');
  parser.href = url;
  return /^.*\..*$/.test(parser.hostname);
};

// Return a minimally valid web url based on input string. Or null if input is invalid.
const ensureValidUrl = originalUrl => {
  const url = prependUrlScheme(originalUrl);
  return hasTopLevelDomain(url) ? url : null;
};

export default ensureValidUrl;