无法在ES6猫鼬扩展模型中调用save()

Question

我试图用ES6语法扩展一个猫鼬模型。虽然我可以调用成功的find({})从mongo数据库中检索数据，但无法调用save()来保存数据。这两种方法都在模型内部执行。

返回的错误是Error: TypeError: this.save is not a function

const mongoose = require('mongoose')
const {Schema, Model} = mongoose

const PersonSchema = new Schema(
  {
    name: { type: String, required: true, maxlength: 1000 }
  },
  { timestamps: { createdAt: 'created_at', updatedAt: 'update_at' } }
)

class PersonClass extends Model {
  static getAll() {
    return this.find({})
  }
  static insert(name) {
    this.name = 'testName'
    return this.save()
  }
}

PersonSchema.loadClass(PersonClass);
let Person = mongoose.model('Persons', PersonSchema); // is this even necessary?

(async () => {
  try {
    let result = await Person.getAll() // Works!
    console.log(result)
    let result2 = await Person.insert() // FAILS
    console.log(result2)
  } catch (err) {
    throw new Error(err)
  }
})()

使用: Nodejs 7.10猫鼬5.3.15

Answer 1

这很正常。您正在尝试从non static方法访问static方法。

你需要这样做：

static insert(name) {
    const instance = new this();
    instance.name = 'testName'
    return instance.save()
}

一些工作实例：

​

class Model {
  save(){
    console.log("saving...");
    return this;
  }
}


class SomeModel extends Model {

  static insert(name){
    const instance = new this();
    instance.name = name;
    return instance.save();
  }

}

const res = SomeModel.insert("some name");
console.log(res.name);

​

下面是一个例子，说明什么是有效的，哪些是不起作用的。

​

class SomeParentClass {
  static saveStatic(){
     console.log("static saving...");
  }
  
  save(){
    console.log("saving...");
  }
}

class SomeClass extends SomeParentClass {
  static funcStatic(){
    this.saveStatic();
  }
  
  func(){
    this.save();
  }
  
  static funcStaticFail(){
    this.save();
  }
}

//works
SomeClass.funcStatic();

//works
const sc = new SomeClass();
sc.func();

//fails.. this is what you're trying to do.
SomeClass.funcStaticFail();

​