docs: protected String getJsFunctionInitialization(String fileName, int numFunction) {
          fileName = fileName.replace("\\", "\\\\").replace("'", "\\'");
          StringBuilder sb = new StringBuilder(format("if (! _$jscoverage['%s'].functionData) {\n", fileName));
          sb.append(format("  _$jscoverage['%s'].functionData = [];\n", fileName));
          for ( int i = 0; i < numFunction; ++i) {
              sb.append(format(initFunction, fileName, i));
          }
          sb.append("}\n");
          return sb.toString();
      }