如何防止mongoose save()创建一些模式默认值？

const schema = new mongoose.Schema({
  name: { type: String, default: 'John' },
  age: { type: Number, default: 25 }
}, { strict: 'throw' });

const schema = new mongoose.Schema({
  name: { type: String, default: 'John' },
  age: { type: Number, default: 25 }
}, { validateBeforeSave: false });

const schema = new mongoose.Schema({
  name: { type: String, default: 'John' },
  age: { type: Number, default: 25 }
});

schema.pre('save', function(next) {
  if (this.isNew) {
    this.name = undefined;
    this.age = undefined;
  }
  next();
});