recursive-layer-search-in-selection.js

var selection = context.selection
var shapeGroups = []

function searchInLayer(layer) {
  switch (layer.class())) {
    case MSPage:
    case MSLayerGroup:
    case MSArtboardGroup:
      let sublayers = layer.layers()
      for (let i = 0; i < sublayers.count(); i++) {
        let sublayer = sublayers.objectAtIndex(i);
        if(sublayer.class() == 'MSShapeGroup') {
          shapeGroups.push(sublayer)
        }
        searchInLayer(sublayer);
      }
      break;
  }
}


for (let i = 0; i < selection.count(); i++) {
  searchInLayer(selection[i], true);
}