Angular组件中如何获取嵌套结构的最顶层对象？

我正在基于Angular构建类似jQuery Builder的查询生成器，目前卡在数据传递环节。点击addGroup、addRule按钮时，新组会被添加到指定层级的数组里，但我希望在addComponent方法中能获取到包含新增内容的完整嵌套对象结构（支持n层嵌套）。

初始数据结构示例：

{
  "condition": "AND",
  "rules": [
    {
      "id": "price",
      "field": "price",
      "type": "double",
      "input": "number",
      "operator": "less",
      "value": 10.25
    }
  ],
  "valid": true
}

添加新组后的结构示例：

{
  "condition": "AND",
  "rules": [
    {
      "id": "price",
      "field": "price",
      "type": "double",
      "input": "number",
      "operator": "less",
      "value": 10.25
    },
    {
      "condition": "OR",
      "rules": [
        {
          "id": "category",
          "field": "category",
          "type": "integer",
          "input": "select",
          "operator": "equal",
          "value": 2
        },
        {
          "id": "category",
          "field": "category",
          "type": "integer",
          "input": "select",
          "operator": "equal",
          "value": 1
        }
      ]
    }
  ],
  "valid": true
}

内容的提问来源于stack exchange，提问作者Vivek