如何检查mongoose mongodb中是否存在旧的模型或模式

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

const schema = new mongoose.Schema({
  name: String,
  age: Number
});

const Model = mongoose.model('Model', schema);

if (mongoose.connection.models['Model']) {
  console.log('Model exists');
} else {
  console.log('Model does not exist');
}

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

const schema = new mongoose.Schema({
  name: String,
  age: Number
});

const Model = mongoose.model('Model', schema);

if (mongoose.connection.models['Model']) {
  console.log('Model exists');
} else {
  console.log('Model does not exist');
}