Inheriting Mongoose schemas

Question

I wanted to make a base 'Entity Schema', and other model entities would inherit from it. I did it, kinda, but then strange thing happened.

Those are my schemas:

• AbstractEntitySchema
• MessageSchema
• UserSchema
• RoomSchema

File: https://github.com/mihaelamj/nodechat/blob/master/models/db/mongo/schemas.js

But in MongoDB, they are all saved in the same document store: 'entity models' not separate ones, like Messages, Users.. Did I get what was supposed to happen, but not what I wanted, separate stores? If so I will just make a basic JSON/object as entity and append the appropriate properties for each entity. Or is there a better way? Thanks.

Answer 1

Since ES6 this works as well:

var ImageSchema: Schema = new Schema({
    ...CommonMetadataSchema.obj,
    src: String,
    description: String,
});

Answer 2

If you want multiple overlapping models with different MongoDB collections, then you use this approach:

function extendSchema (Schema, definition, options) {
  return new mongoose.Schema(
    Object.assign({}, Schema.obj, definition),
    options
  );
}

Example

const extendSchema = require('mongoose-extend-schema');

const UserSchema = new mongoose.Schema({
  firstname: {type: String},
  lastname: {type: String}
});

const ClientSchema = extendSchema(UserSchema, {
  phone: {type: String, required: true}
});

You simply extend the original object the schema was created with and recreate a new schema on its basis. This is some sort of abstract schema which you inherit from.

Check this npm module: https://www.npmjs.com/package/mongoose-extend-schema