JS 数组对象根据某一相同key合并成新的数组

<script>
let labels = [{"id": 2, "name": "艾瑞", "label": "A"}, {"id": 4, "name": "大时代", "label": "D"}, {"id": 1, "name": "道合顺", "label": "D"}, {"id": 5, "name": "小米", "label": "X"},{"id": 3, "name": "知乎", "label": "Z"}];
function alpha_sort(labels){
   let alpha_dict = new Object();
   let factories = new Array();
   for(var i=0;i<labels.length;i++){
      let factory = labels[i];
      let label = factory.label;
      if(alpha_dict[label] == undefined){
         factories.push({"label": label, "children": [factory]});
         alpha_dict[label] = factories.length -1;
      }else {
           factories[alpha_dict[label]].children.push(factory);
      }
   }
   console.log(alpha_dict);
   console.log(factories);
   return factories;
}
console.log(alpha_sort(labels))
</script>