NODE-3962 Description

What problem are you facing?

I'm using https://github.com/vega/ts-json-schema-generator to generate JSON Schema that validates my types. When some object got a property that have an ObjectId type, the generated JSON schema has the rule (besides others):

 
properties: {
_bsontype: {
type: 'string',
const: 'ObjectID',
{color:#9abdf5}},
{color:#89ddff}}

However an ObjectId instance _bsontype property is equal to ObjectId (lowercase d).

What driver and relevant dependency versions are you using?

Node 16.13.2

BSON 4.6.1

Steps to reproduce?

1/ In the source file, check https://github.com/mongodb/js-bson/blob/8305bdf333a4ddec99121b42d9477958342b0fda/src/objectid.ts#L31 : bsontype!: 'ObjectId'

2/ A node script test.mjs

import { ObjectId ] from 'bson';
console.log((new ObjectId())._bsontype); // echoes ObjectID

My understanding is that it should be either always ObjectId, or always ObjectID.