如何在猫鼬中创建2dsphere索引？

Question

我有一个节点/快速服务器。由于猫鼬，我已经连接到mongo数据库。我创建了一个带有位置字段的架构，并为其添加了索引。执行聚合时，mongo声称：

$ geoNear需要2d或2dsphere索引

这是我的代码：

const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const userSchema = new Schema(
  {
    username: { type: String, required: true, unique: true },
    email: { type: String, required: true, unique: true },
    password: { type: String, required: true },
    age: {type: Number},
    location: {
      type: { type: String, enum: ["Point"] },
      coordinates: { type: [Number] },
    },
  },
  { timestamps: true }
);


userSchema.index({ age: 1, location: "2dsphere"});

module.exports = mongoose.model("User", userSchema);

以下是汇总：

 User.aggregate([
        {$geoNear: {
            near: { type: "Point", coordinates: location },
            distanceField: "dist.calculated",
            maxDistance,
          }},
        {$match: {
            age: { $gte: minAge, $lte: maxAge },
          }},
      ]).exec((_, data) => res.json({ data })
      );

这是猫鼬的初始化：

// Connect to MongoDB and start server
mongoose
  .set("useFindAndModify", false)
  .connect(process.env.MONGODB, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
    useCreateIndex: true,
    autoIndex: false,
  })
  .then(() =>
    server.listen(process.env.PORT, () =>
      console.log(`server is listening on ${process.env.PORT}!`)
    )
  )
  .catch((err) => console.log("error", err));

这有什么问题？