SchemaDefinitionProperty doesn't work with number type

[devagrawal09]

Do you want to request a feature or report a bug?
Bug (typescript)
What is the current behavior?
Sample code:

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

interface IProfile { age: number; }

interface ProfileDoc extends Document, IProfile {}

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

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

The last line gives me these errors:

Argument of type '{ age: SchemaDefinitionProperty<number>; }' is not assignable to parameter of type '{ [path: string]: SchemaDefinitionProperty<undefined>; }'.
  Property 'age' is incompatible with index signature.
    Type 'SchemaDefinitionProperty<number>' is not assignable to type 'SchemaDefinitionProperty<undefined>'.
      Type 'number' is not assignable to type 'SchemaDefinitionProperty<undefined>'.

Error goes away if I change the interface definition to

interface IProfile { age: Number; }

But tslint's recommended rules include banning the usage of the Number type.

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?
The interface can be defined with number type and typescript does not throw 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

[vkarpov15]

One potential workaround is to just get rid of the generic param to SchemaDefinition: const ProfileSchemaDef: SchemaDefinition = { age: Number }; . We took a closer look at this and it seems like the best way to get this to work correctly is by adding a 3rd generic param to Schema that helps with typechecking your schema definition as suggested in #9789

[vkarpov15]

You'll have to do this to help Mongoose infer the type of age re: #9789:

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

interface IProfile { age: number; }

interface ProfileDoc extends Document, IProfile {}

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

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