const BoxConstraints.tightForFinite({double width: double.INFINITY, double height: double.INFINITY })

Creates box constraints that require the given width or height, except if they are infinite.

Source

const BoxConstraints.tightForFinite({
  double width: double.INFINITY,
  double height: double.INFINITY
}): minWidth = width != double.INFINITY ? width : 0.0,
    maxWidth = width != double.INFINITY ? width : double.INFINITY,
    minHeight = height != double.INFINITY ? height : 0.0,
    maxHeight = height != double.INFINITY ? height : double.INFINITY;