airgap.js optimized URL parser screenshot

airgap.js-optimized-url-parser-screenshot.ts

/**
 * Parses potentially stringifiable URL input into a URL instance and returns null if the input is
 * an invalid URL or if the input is a data URI, as processing those uses significant resources and we
 * don't need to regulate them anyway.
 *
 * Implemented with four tiers:
 * 1. fastest: URL.parse()
 * 2. second fastest: URLPattern validation + new URL()
 * 3. fast for absolute URLs: DOM validation + new URL() for absolute URLs / try...catch new URL() for relative URLs
 * 4. slowest: try...catch new URL()
 *
 * @param input - Stringifiable URL input (e.g. a string or URL instance)
 * @param context - Context URL
 * @returns Parsed URL or null
 */
export const parsePotentialURL: (
  input: unknown,
  context?: URL | Stringifiable,
) => URL | null = parseURLSafe
  ? // native URL.parse() is supported
    (input, context) => (isDataURI(input) ? null : parseURLSafe(input, context))
  : validateURL
    ? // URLPattern validator can be used instead of try...catch
      (input, context) =>
        !isDataURI(input) && validateURL(input)
          ? parseURL(input, context)
          : null
    : HAS_DOM
      ? // if DOM is available, use input[type=url] validation for absolute URLs
        (() => {
          const validator = document.createElementNS(
            HTML_NS,
            'input',
          ) as HTMLInputElement;
          validator.type = 'url';
          const validityState = validator.validity;
          const setValue = getPropertyDescriptor(HTMLInputElement, 'value').set;
          const getValidity = getPropertyDescriptor(ValidityState, 'valid').get;
          return (
            input: unknown,
            context: URL | Stringifiable = locationHref,
          ) => {
            if (isDataURI(input)) {
              return null;
            }
            // DOM can only validate absolute urls, so we still have to fallback
            // to parseAndValidateURL for everything that doesn't pass this check
            call(setValue, validator, input);
            return call(getValidity, validityState)
              ? parseURL(input, context)
              : parseAndValidateURL(input, context);
          };
        })()
      : parseAndValidateURL;