is-valid-url.ts

/**
 * Returns whether a string is a valid URL
 */
export function isValidUrl(str: string): boolean {
  const pattern = new RegExp(
    '^' +
      // protocol identifier
      '(?:(?:https?|ftp)://)' +
      // user:pass authentication
      '(?:\\S+(?::\\S*)?@)?' +
      '(?:' +
      // IP address exclusion
      // private & local networks
      '(?!(?:10|127)(?:\\.\\d{1,3}){3})' +
      '(?!(?:169\\.254|192\\.168)(?:\\.\\d{1,3}){2})' +
      '(?!172\\.(?:1[6-9]|2\\d|3[0-1])(?:\\.\\d{1,3}){2})' +
      // IP address dotted notation octets
      // excludes loopback network 0.0.0.0
      // excludes reserved space >= 224.0.0.0
      // excludes network & broacast addresses
      // (first & last IP address of each class)
      '(?:[1-9]\\d?|1\\d\\d|2[01]\\d|22[0-3])' +
      '(?:\\.(?:1?\\d{1,2}|2[0-4]\\d|25[0-5])){2}' +
      '(?:\\.(?:[1-9]\\d?|1\\d\\d|2[0-4]\\d|25[0-4]))' +
      '|' +
      // host name
      '(?:(?:[a-z\\u00a1-\\uffff0-9]-*)*[a-z\\u00a1-\\uffff0-9]+)' +
      // domain name
      '(?:\\.(?:[a-z\\u00a1-\\uffff0-9]-*)*[a-z\\u00a1-\\uffff0-9]+)*' +
      // TLD identifier
      '(?:\\.(?:[a-z\\u00a1-\\uffff]{2,}))' +
      // TLD may end with dot
      '\\.?' +
      ')' +
      // port number
      '(?::\\d{2,5})?' +
      // resource path
      '(?:[/?#]\\S*)?' +
      '$',
    'i'
  );

  return pattern.test(str);
}