聚合对象的嵌套数组

Question

我具有以下文档结构：

import * as React from "react";

export default class Pagination extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      pages: this.findNumberOfPages()
    };
    this.findNumberOfPages = this.findNumberOfPages.bind(this)
  }
  componentDidMount() {
    console.log(this.props);
  }
  componentDidUpdate(prevProps) {
    if(prevProps.dataCount != this.props.dataCount){
      this.setState({ pages: this.findNumberOfPages() });
    }
  }

  findNumberOfPages() {
    return Math.ceil(this.props.dataCount / 10);
  }

  renderPageNumbers = () => {
    const numberOfPages = this.findNumberOfPages()
    let pages = [];
    for (let i = 1; i <= numberOfPages; i++) {
      pages.push(<span key={i}>{i}</span>);
    }
    return pages;
  };

  render() {
    return (
      <>
        {this.props.currentPage > 1 ? <span>Prev</span> : ""}
        {this.renderPageNumbers()}
        {this.props.currentPage < this.state.pages ? <span>Next</span> : ""}
      </>
    );
  }
}

我想做的是每分钟选择所有文档，然后计算每个传感器的平均值并得到如下结果：

{
  "_id": "5d2708ff79263ba40e54c08c",
  "meta": {
    "uid": "dd41ca10-a3c2-11e9-a1dd-fbec9d04cb25",
    "firmware": "0.0.1",
    "timestamp": "2019-07-11T10:01:35.264Z"
  },
  "sensors": [
    {
      "_id": "5d2708ff79263ba40e54c08e",
      "name": "sensor1",
      "value": 0.09050827850822706
    },
    {
      "_id": "5d2708ff79263ba40e54c08d",
      "name": "sensor2",
      "value": 0.06592630654288716
    }
  ]
}

多年使用关系数据库后，这有点令人困惑。