code: function declareRootElement( def, code ) {
      const rootElementName = buildElement( def, code );
  
      code.section.elements.define.push( "//-----------------------" );
      code.section.elements.define.push( "// Declare root element." );
      code.section.elements.define.push(
          "Object.defineProperty( this, '$', {",
          [
              `value: ${rootElementName}.$,`,
              "writable: false, ",
              "enumerable: false, ",
              "configurable: false"
          ],
          "});"
      );
  }
docs: Javascript for for root variable declaration.
  
  @param  {object} def - `{View ...}`
  @param  {Template} code - Helper to write the Javascript code.
  
  @return {undefined}