code: @GwtIncompatible("Unnecessary")
    private String getMapPath(String outputFile) {
      String basePath = "";
  
      if (outputFile.isEmpty()) {
        // If we have a js_module_binary rule, output the maps
        // at modulename_props_map.out, etc.
        if (!config.moduleOutputPathPrefix.isEmpty()) {
          basePath = config.moduleOutputPathPrefix;
        } else {
          basePath = "jscompiler";
        }
      } else {
        // Get the path of the output file.
        File file = new File(outputFile);
  
        String outputFileName = file.getName();
  
        // Strip the .js from the name.
        if (outputFileName.endsWith(".js")) {
          outputFileName =
              outputFileName.substring(0, outputFileName.length() - 3);
        }
  
        String fileParent = file.getParent();
        if (fileParent == null) {
          basePath = outputFileName;
        } else {
          basePath = file.getParent() + File.separatorChar + outputFileName;
        }
      }
  
      return basePath;
    }
docs: Returns the path at which to output map file(s) based on the path at which the JS binary will
  be placed.
  
  @return The path in which to place the generated map file(s).