code: function hasFileWithHigherPriorityExtension(file, literalFiles, wildcardFiles, extensions, keyMapper) {
          var extensionPriority = ts.getExtensionPriority(file, extensions);
          var adjustedExtensionPriority = ts.adjustExtensionPriority(extensionPriority);
          for (var i = 0 /* Highest */; i < adjustedExtensionPriority; i++) {
              var higherPriorityExtension = extensions[i];
              var higherPriorityPath = keyMapper(ts.changeExtension(file, higherPriorityExtension));
              if (higherPriorityPath in literalFiles || higherPriorityPath in wildcardFiles) {
                  return true;
              }
          }
          return false;
      }
docs: Determines whether a literal or wildcard file has already been included that has a higher
  extension priority.
  
  @param file The path to the file.
  @param extensionPriority The priority of the extension.
  @param context The expansion context.