Mongoose：预处理钩子不按预期工作

Question

我需要在保存Mongo文档之前进行一些计算，但是预处理函数没有触发。

我正在使用mongoose ORM，示例：

const mongoose = require("mongoose");
const Schema = mongoose.Schema;

const TradeSchema = new Schema(
  {
    id: { type: Number, required: true, unique: true, default: 1 },
    type: { type: String, required: true, enum: ["sell", "buy"] },
    user_id: { type: Number, required: true, unique: true },
    symbol: { type: String, required: true },
    shares: { type: Number, required: true, min: 1, max: 100 },
    price: { type: Number, required: true },
    timestamp: { type: Number, required: true }
  },
  { versionKey: false }
);

const Trade = mongoose.model("Trades", TradeSchema);

//try 1
TradeSchema.pre("validate", true, function(next) {
  console.log("validate true");
});

//try 2
TradeSchema.pre("save", true, function(next) {
  console.log("save true");
});

//try 3
TradeSchema.pre("validate", function(next) {
  console.log("validate");
});

//try 4
TradeSchema.pre("save", function(next) {
  console.log("save");
});

const trade = new Trade({
  type: "buy",
  user_id: 1234,
  symbol: "cdcd",
  shares: 11,
  price: 1234,
  timestamp: 1234,
  id: 12
});
trade
  .save()
  .then(console.log)
  .catch(console.error);

我按照文档和社区的建议尝试了多个预处理函数，但对我来说都不起作用，请帮忙！

- Raghu Chahar

Answer 1

将 const Trade = mongoose.model("Trades", TradeSchema); 放在文件末尾，并在 pre hook() 中使用 next()，每个 pre hook 只需使用一个实例，所以请尝试。保留 html 标签。

const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const TradeSchema = new Schema(
  {
    id: { type: Number, required: true, unique: true, default: 1 },
    type: { type: String, required: true, enum: ["sell", "buy"] },
    user_id: { type: Number, required: true, unique: true },
    symbol: { type: String, required: true },
    shares: { type: Number, required: true, min: 1, max: 100 },
    price: { type: Number, required: true },
    timestamp: { type: Number, required: true }
  },
  { versionKey: false }
);



//try 1
TradeSchema.pre("validate", true, function(next) {
  console.log("validate true");
  next()
});

//try 2
TradeSchema.pre("save", true, function(next) {
  console.log("save true");
  next()
});

const Trade = mongoose.model("Trades", TradeSchema);
module.exports = Trade

- Mohammad Yaser Ahmadi

---

谢谢，Mohammad，现在它可以工作了，在所有钩子完成后调用mongoose.model()对我有帮助。 - Raghu Chahar