javascript - Applying a single leaflet search control to search multiple layers?

I am attempting to add a single search button to look through geoJSON layers. They will look through the field "name". Unfortunately, my method of creating a layer group is not working. What am I missing? Or how do I group together geoJSON files to make this work?

var searchControl = new L.Control.Search({
      layer: [syriaLayer, countryBoundary],

      zoom: 7.5,
      propertyName: 'Sheet_Numb',
      circleLocation: false
  });

Answer

Group the layers within a layerGroup or a featureGroup as described in the docs

layer: L.featureGroup([syriaLayer, countryBoundary]),