Schema Type is inferred as a Partial when assigning schema definition to a variable

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

6.4.1

Node.js version

16.13.0

MongoDB server version

5.0

Description

When assigning the schema definition to a variable instead of directly passing it to the schema constructor the resulting type has all properties inferred as optionals.

Steps to Reproduce

import { Schema, InferSchemaType } from 'mongoose';

const schemaDefintion = {
  name: { type: String, required: true },
  email: { type: String, required: true },
  avatar: String,
};

// Schema
const schema = new mongoose.Schema(schemaDefintion);

type User = InferSchemaType<typeof schema>;
// InferSchemaType will determine the type as follows:
//  type User = {
//     name?: string | undefined;
//     email?: string | undefined;
//     avatar?: string | undefined;
// }

Expected Behavior

type User = InferSchemaType<typeof schema>;
// InferSchemaType will determine the type as follows:
// type User = {
//     name: string;
//     email: string;
//     avatar?: string | undefined;
// }

[vkarpov15]

@mohammad0-0ahmad is correct, the right way to do this is as const;. TS is currently unable to figure out that schemaDefinition isn’t modified in any way, so new mongoose.Schema(schemaDefintion); is not equivalent to new mongoose.Schema({ name: { type: String, required: true }, ... }) as far as TS is concerned, unless you add the as const;.

[mohammad0-0ahmad]

@heilmela test this:

import { Schema, InferSchemaType } from 'mongoose';

const schemaDefintion = {
  name: { type: String, required: true },
  email: { type: String, required: true },
  avatar: String,
} as const;

const schema = new mongoose.Schema(schemaDefintion);

type User = InferSchemaType<typeof schema>;