Schema definition does not accept Schema instance as a value

[devagrawal09]

Do you want to request a feature or report a bug?
Report a bug
What is the current behavior?
Here is the sample code

import { Document, Schema, SchemaDefinition } from "mongoose";

interface IProfile {
  age: Number;
}

interface ProfileDoc extends Document, IProfile {}

interface IUser {
  email: string;
  profile: IProfile;
}

interface UserDoc extends Document, IUser {};

const ProfileSchemaDef: SchemaDefinition<IProfile> = {
  age: Schema.Types.Number
};

const ProfileSchema = new Schema<ProfileDoc>(ProfileSchemaDef);

const UserSchemaDef: SchemaDefinition<IUser> = {
  email: String,
  profile: ProfileSchema
};

This code gives me the following error on the profile: ProfileSchema line

Type 'Schema<ProfileDoc, Model<ProfileDoc>>' is not assignable to type 'Schema<Document<any>, Model<Document<any>>>'.

However if I change it to profile: ProfileSchemaDef, the error goes away.

I looked into mongoose's .d.ts file, and it looks like the SchemaDefinitionProperty type is correctly expecting a Schema type. But when I give it a Schema instance, it fails. So I have to resort to providing a SchemaDefinition<T> instance.

If the current behavior is a bug, please provide the steps to reproduce.

Code provided above.

{
  "compilerOptions": {
    "target": "es2017",
    "module": "commonjs",
    "lib":["ES2020"],
    "allowJs": true,
    "outDir": "build",
    "rootDir": ".",
    "sourceMap": true,

    "moduleResolution": "node",
    "baseUrl": "./src",
    "esModuleInterop": true,

    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    
    "preserveConstEnums": true,
    "resolveJsonModule": true,
    "pretty": true,
  },
  "include": ["src", "test"],
  "exclude": ["node_modules", "**/*.spec.ts"]
}

What is the expected behavior?
profile: ProfileSchema should not result in errors.

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
Node v12.15.0, mongoose v5.11.11

[devagrawal09]

Update:
I changed

const ProfileSchema = new Schema<ProfileDoc>(ProfileSchemaDef);

to

const ProfileSchema = new Schema<ProfileDoc, any>(ProfileSchemaDef);

and now the UserSchemaDef seems to accept it just fine. However this is not the ideal solution.

[devagrawal09]

One more update:
Getting rid of the type argument for Schema also fixed the issue.

const ProfileSchema = new Schema(ProfileSchemaDef);

This seems like a much more ideal solution. However, I still think the the original form of the definition should work, since ProfileDoc is an extension of IProfile. Please let me know if you disagree.

[vkarpov15]

Part of the issue is that the type of profile in IUser needs to inherit from Document. The below code will work once we ship Mongoose 5.11.15:

import { Document, Schema, SchemaDefinition, Model } from "mongoose";

interface IProfile {
  age: Number;
}

interface ProfileDoc extends Document, IProfile {}

interface IUser {
  email: string;
  profile: ProfileDoc; // <-- changed
}

interface UserDoc extends Document, IUser {};

const ProfileSchemaDef: SchemaDefinition<IProfile> = {
  age: Schema.Types.Number
};

const ProfileSchema = new Schema<ProfileDoc, Model<ProfileDoc>, ProfileDoc>(ProfileSchemaDef); // <-- added generics

const UserSchemaDef: SchemaDefinition<IUser> = {
  email: String,
  profile: ProfileSchema
};