BigInt type doesn't work as expected

[akim-bow]

Prerequisites

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

Mongoose version

8.0.2

Node.js version

18.x

MongoDB server version

6.x

Typescript version (if applicable)

5.2.2

Description

When i use BigInt type in mongoose schema, i cannot pass typecheck and assign BigInt value to it's property.

Steps to Reproduce

export const affiliateSchema = new Schema({
  balance: { type: BigInt, default: BigInt(0) },
});

const AffiliateModel = model("Affiliate", affiliateSchema);

AffiliateModel.findOne({})!.then(modelValue => {
  modelValue.balance = 123n;
});

Expected Behavior

No type error here.

[akim-bow]

Currently i can fix it with a hacky type like this

export type AffiliateSchema = Omit<InferSchemaType<typeof affiliateSchema>, 'balance'> & {
  balance: bigint;
};

[vkarpov15]

Workaround is to do type: 'BigInt' in your schema as follows:

import mongoose from 'mongoose';

export const affiliateSchema = new mongoose.Schema({
  balance: { type: 'BigInt', default: BigInt(0) },
});

const AffiliateModel = mongoose.model("Affiliate", affiliateSchema);

AffiliateModel.findOne({}).orFail().then(modelValue => {
  modelValue.balance = 123n;
});