of method

TextDirection of (BuildContext context)

The text direction from the closest instance of this class that encloses the given context.

If there is no Directionality ancestor widget in the tree at the given context, then this will return null.

Typical usage is as follows:

TextDirection textDirection = Directionality.of(context);

Implementation 

static TextDirection of(BuildContext context) {
  final Directionality widget = context.inheritFromWidgetOfExactType(Directionality);
  return widget?.textDirection;
}