Function relativeIfPossible

packages/next/src/compiled/source-map08/source-map.js:2738–2767

(rootURL, targetURL)

exports.relative = relative;

function relativeIfPossible(rootURL, targetURL) {
  const urlType = getURLType(rootURL);
  if (urlType !== getURLType(targetURL)) {
    return null;
  }

  const base = buildSafeBase(rootURL + targetURL);
  const root = new URL(rootURL, base);
  const target = new URL(targetURL, base);

  try {
    new URL("", target.toString());
  } catch (err) {
    // Bail if the URL doesn't support things being relative to it,
    // For example, data: and blob: URLs.
    return null;
  }

  if (
    target.protocol !== root.protocol ||
    target.user !== root.user ||
    target.password !== root.password ||
    target.hostname !== root.hostname ||
    target.port !== root.port
  ) {
    return null;
  }

  return computeRelativeURL(root, target);
}

/**
 * Compute the URL of a source given the the source root, the source's