code: function FeatureCollection(input){
      if(input && input.type === "FeatureCollection" && input.features){
        extend(this, input);
      } else if(isArray(input)) {
        this.features = input;
      } else {
        throw "Terraformer: invalid input for Terraformer.FeatureCollection";
      }
  
      this.type = "FeatureCollection";
    }
docs: /*
  GeoJSON FeatureCollection Class
  new FeatureCollection();
  new FeatureCollection([feature, feature1]);
  new FeatureCollection({
  type: "FeatureCollection",
  coordinates: [feature, feature1]
  });