Question

我有一个Fee模式，用于保存费用支付的详细信息，这些详细信息具有student属性的引用，该属性是对Student模式的引用，告诉谁支付了费用。

const mongoose = require('mongoose');
const Schema   = mongoose.Schema;
const Student  = require('./student');

const fee = new Schema({
  student: { // Student ID
    type: Schema.Types.ObjectId,
    ref: 'Student'
  },
  paidFor: {
    type: Date
  },
  paidOn: {
    type: Date,
    default: Date.now
  },
  due: Number,
  fine: Number,
  late: Number,
  misc: Number,
  tution: Number,
  library: Number,
  admission: Number,
  development: Number,
  electricity: Number,
  examination: Number
});

// This pre save middleware to check if the Student ID belongs to some student or not.
fee.pre('save', function(next) {
  const { student } = this;
  Student.findOne({ _id: student }, (error, result) => {
    if (error) {
      return next(new Error(error));
    }
    if (!result) { // If student not found.
      return next(new Error("Student not found."));
    }
    return next();
  });
});

module.exports = new mongoose.model("Fee", fee);

问题出在pre('save')...中间件上。当我为它提供一个有效的student id时，它属于Student集合中的某个文档，它将按预期方式成功通过pre('save')...中间件后将其成功保存。但是当我给它一个student id集合中不属于任何文档的Student时，它并没有保存我想要的内容，但是它给空对象作为错误 。我上面通过时，错误对象没有像"Student not found."这样的消息。

我在Mongoose Docs和this answer中尝试了解决方案，但没有任何效果。

请告诉我其背后的原因以及如何解决。谢谢。

Answer 1

删除您要传递给struct ContentView: View { private let x: Double = 200.0 private let y: Double = 200.0 private let radius: CGFloat = 100.0 var body: some View { GeometryReader { geo in Rectangle() .foregroundColor(Color.black) Path { path in path.addArc(center: CGPoint(x: self.x, y: self.y), radius: self.radius, startAngle: .degrees(0), endAngle: .degrees(360), clockwise: true) } .fill(RadialGradient( gradient: Gradient(colors: [.red, .blue]), center: UnitPoint( x: CGFloat(self.x / Double(geo.size.width)), y: CGFloat(self.y / Double(geo.size.height)) ), startRadius: self.radius * 0.30, endRadius: self.radius )) } } }的虚假ID 或者只是让猫鼬创建一个新的mongoose.Schema.ObjectId(*YOUR_STRING_ID*)

猫鼬预保存中间件错误为空对象

1 个答案: