wix-style-react/src/utils/UrlUtils.js

wix-style-react

/**
 * RegExps.
 * A URL must match #1 and then at least one of #2/#3.
 * Use two levels of REs to avoid REDOS.
 */

const protocolAndDomainRE = /^(?:\w+:)?\/\/(\S+)$/;
const protocolRE = /^https?:\/\/.+$/i;

const localhostDomainRE = /^localhost[\:?\d]*(?:[^\:?\d]\S*)?$/;
const nonLocalhostDomainRE = /^[^\s\.]+\.\S{2,}$/;

/**
 * Loosely validate a URL `string`.
 *
 * @param {String} string
 * @return {Boolean}
 */

export function isUrl(string) {
  if (typeof string !== 'string') {
    return false;
  }

  const match = string.match(protocolAndDomainRE);
  if (!match) {
    return false;
  }

  const everythingAfterProtocol = match[1];
  if (!everythingAfterProtocol) {
    return false;
  }

  return (
    localhostDomainRE.test(everythingAfterProtocol) ||
    nonLocalhostDomainRE.test(everythingAfterProtocol)
  );
}

/**
 * Prepend `http://` to relative url.
 *
 * @param {String} url
 * @return {String}
 */
export const prependHTTP = url =>
  url && (protocolRE.test(url) ? url : `http://${url}`);