Mongoose Schema 类型作为来自 TypeScript 的自定义接口？

Question

I´d like to store a custom object that has the StationRating interface attributes, can somebody help me?

Answer 1

It's possible, but it requires some boilerplate. Issues are:

• Interfaces and types in TS do not exist in emitted code

• While you could go in the other direction - create a schema object and make an interface/type out of it - schema object values must be constructors , eg Number , which is not the same thing as something with a number type.

But you can create a type that maps the constructor types to their primitive types (eg Number to number ), then use that to turn the schema object into the type you want:

type ConstructorMapping<T> =
    T extends NumberConstructor ? number :
    T extends StringConstructor ? string : never; // etc: continue as needed

const schemaObj = {
  score: Number,
  user_id: String,
  station_id: String,
  description: String,
};

type SchemaObj = typeof schemaObj;
type StationRating = {
    [prop in keyof SchemaObj]: ConstructorMapping<SchemaObj[prop]>
};

Then use schemaObj when calling new Schema , and you'll also have the following usable type:

type StationRating = {
    score: number;
    user_id: string;
    station_id: string;
    description: string;
}

Is it worth it? I'm not sure. For smaller objects, maybe not. For larger objects, maybe so. You might prefer just to write out the type and the schema object.

Answer 2

Is there a specific reason you want to store it in an object? You could use a virtual method to create the "Rating". I'm not exactly sure without seeing more, but if all you want to do is reference the score or create some calculations off it, then it seems like an easy enough solution. https://mongoosejs.com/docs/tutorials/virtuals.html

const userSchema = mongoose.Schema({
  firstName: String,
  lastName: String
});
// Create a virtual property `fullName` with a getter and setter.
userSchema.virtual('fullName').
  get(function() { return `${this.firstName} ${this.lastName}`; }).
  set(function(v) {
    // `v` is the value being set, so use the value to set
    // `firstName` and `lastName`.
    const firstName = v.substring(0, v.indexOf(' '));
    const lastName = v.substring(v.indexOf(' ') + 1);
    this.set({ firstName, lastName });
  });
const User = mongoose.model('User', userSchema);

const doc = new User();
// Vanilla JavaScript assignment triggers the setter
doc.fullName = 'Jean-Luc Picard';

doc.fullName; // 'Jean-Luc Picard'
doc.firstName; // 'Jean-Luc'
doc.lastName; // 'Picard'