小猫不会说话

Question

我正在浏览mongoose quickstart并且我的应用程序因{1}}错误而死于fluffy.speak()

教程中的我（稍加修改）代码：

TypeError: Object { name: 'fluffy', _id: 509f3377cff8cf6027000002 } has no method 'speak'

Answer 1

当您致电db.model时，模型将根据您的架构进行编译。就在那时，schema.methods被添加到模型的原型中。因此，您需要在之前定义架构上的任何方法。从中创建模型。

// ensure this method is defined before...
kittySchema.methods.speak = function() {
    var greeting = this.name ? "Meow name is" + this.name : "I don't have a name";
    console.log(greeting);
}

// ... this line.
var Kitten = db.model('Kitten', kittySchema);

// methods added to the schema *afterwards* will not be added to the model's prototype
kittySchema.methods.bark = function() {
    console.log("Woof Woof");
};

(new Kitten()).bark(); // Error!  Kittens don't bark.