message: Fixes issue with null and "" node labels
diff: @@ -735,7 +735,7 @@ export default class Sigma extends EventEmitter {
  this.quadtree.add(node, data.x, 1 - data.y, data.size / this.width);
  - if (data.label && !data.hidden)
  + if (typeof data.label === "string" && !data.hidden)
  this.labelGrid.add(node, data.size, this.framedGraphToViewport(data, { matrix: nullCameraMatrix }));
  this.nodePrograms[data.type].process(data, data.hidden, nodesPerPrograms[data.type]++);
  