Function normalizeSourceMap

src/utils.js:832–873

(map, resourcePath)

}

function normalizeSourceMap(map, resourcePath) {
  let newMap = map;

  // Some loader emit source map as string
  // Strip any JSON XSSI avoidance prefix from the string (as documented in the source maps specification), and then parse the string as JSON.
  if (typeof newMap === "string") {
    newMap = JSON.parse(newMap);
  }

  delete newMap.file;

  const { sourceRoot } = newMap;

  delete newMap.sourceRoot;

  if (newMap.sources) {
    // Source maps should use forward slash because it is URLs (https://github.com/mozilla/source-map/issues/91)
    // We should normalize path because previous loaders like `sass-loader` using backslash when generate source map
    newMap.sources = newMap.sources.map((source) => {
      // Non-standard syntax from `postcss`
      if (source.indexOf("<") === 0) {
        return source;
      }

      const sourceType = getURLType(source);

      // Do no touch `scheme-relative` and `absolute` URLs
      if (sourceType === "path-relative" || sourceType === "path-absolute") {
        const absoluteSource =
          sourceType === "path-relative" && sourceRoot
            ? path.resolve(sourceRoot, normalizePath(source))
            : normalizePath(source);

        return path.relative(path.dirname(resourcePath), absoluteSource);
      }

      return source;
    });
  }

  return newMap;
}

function getPreRequester({ loaders, loaderIndex }) {
  const cache = Object.create(null);