Function computeSourceURL

lib/util.js:413–443

* Compute the URL of a source given the the source root, the source's * URL, and the source map's URL.

(sourceRoot, sourceURL, sourceMapURL)

 * URL, and the source map's URL.
 */
function computeSourceURL(sourceRoot, sourceURL, sourceMapURL) {
  // The source map spec states that "sourceRoot" and "sources" entries are to be appended. While
  // that is a little vague, implementations have generally interpreted that as joining the
  // URLs with a `/` between then, assuming the "sourceRoot" doesn't already end with one.
  // For example,
  //
  //   sourceRoot: "some-dir",
  //   sources: ["/some-path.js"]
  //
  // and
  //
  //   sourceRoot: "some-dir/",
  //   sources: ["/some-path.js"]
  //
  // must behave as "some-dir/some-path.js".
  //
  // With this library's the transition to a more URL-focused implementation, that behavior is
  // preserved here. To acheive that, we trim the "/" from absolute-path when a sourceRoot value
  // is present in order to make the sources entries behave as if they are relative to the
  // "sourceRoot", as they would have if the two strings were simply concated.
  if (sourceRoot && getURLType(sourceURL) === "path-absolute") {
    sourceURL = sourceURL.replace(/^\//, "");
  }

  let url = normalize(sourceURL || "");

  // Parsing URLs can be expensive, so we only perform these joins when needed.
  if (sourceRoot) url = join(sourceRoot, url);
  if (sourceMapURL) url = join(trimFilename(sourceMapURL), url);
  return url;
}
exports.computeSourceURL = computeSourceURL;