arrowGoesInto function

bool arrowGoesInto(
  1. LogicalKeyboardKey key,
  2. TextDirection dir
)

True when a horizontal arrow key points toward deeper nesting for the given text dir — the arrow a Tree should treat as expand / step-in. In LTR that is the right arrow; in RTL the indent mirrors, so it is the left arrow. The opposite arrow collapses / steps out.

Implementation

bool arrowGoesInto(LogicalKeyboardKey key, TextDirection dir) =>
    horizontalStep(key, dir) > 0;