如何使用node.js和mongoose统计文档集中的词频

const mongoose = require('mongoose');

// 连接到MongoDB数据库
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('Connected to MongoDB');
    // 创建模型
    const DocumentModel = mongoose.model('Document', new mongoose.Schema({
      content: String
    }));

    // 获取所有文档
    DocumentModel.find({}, (err, documents) => {
      if (err) {
        console.error(err);
        return;
      }

      // 统计词频
      const wordFrequencyMap = {};
      documents.forEach((document) => {
        const words = document.content.split(' ');
        words.forEach((word) => {
          if (wordFrequencyMap[word]) {
            wordFrequencyMap[word]++;
          } else {
            wordFrequencyMap[word] = 1;
          }
        });
      });

      // 打印结果
      console.log(wordFrequencyMap);
    });
  })
  .catch((err) => console.error(err));