description

# createElementUpgrader method Null safety

ElementUpgrader createElementUpgrader (

1. Type type,
2. {String? extendsTag}

)

Creates an element upgrader which can be used to change the Dart wrapper type for elements.

The type specified must be a subclass of HtmlElement, when an element is upgraded then the created constructor will be invoked on that element.

If the type is not a direct subclass of HtmlElement then the extendsTag parameter must be provided.

## Implementation

    ElementUpgrader createElementUpgrader(Type type, {String? extendsTag}) {
      return new _JSElementUpgrader(this, type, extendsTag);
    }