Improve serialization performance

Author: SeanReece

src/bson_value.ts

@@ -1,13 +1,14 @@
 import { BSON_MAJOR_VERSION } from './constants';
 import { type InspectFn } from './parser/utils';
+import { BSON_VERSION_SYMBOL } from './constants';
 
 /** @public */
 export abstract class BSONValue {
   /** @public */
   public abstract get _bsontype(): string;
 
   /** @internal */
-  get [Symbol.for('@@mdb.bson.version')](): typeof BSON_MAJOR_VERSION {
+  get [BSON_VERSION_SYMBOL](): typeof BSON_MAJOR_VERSION {
     return BSON_MAJOR_VERSION;
   }
 

src/constants.ts

@@ -1,6 +1,9 @@
 /** @internal */
 export const BSON_MAJOR_VERSION = 6;
 
+/** @internal */
+export const BSON_VERSION_SYMBOL = Symbol.for('@@mdb.bson.version');
+
 /** @internal */
 export const BSON_INT32_MAX = 0x7fffffff;
 /** @internal */

src/extended_json.ts

@@ -6,7 +6,8 @@ import {
   BSON_INT32_MIN,
   BSON_INT64_MAX,
   BSON_INT64_MIN,
-  BSON_MAJOR_VERSION
+  BSON_MAJOR_VERSION,
+  BSON_VERSION_SYMBOL
 } from './constants';
 import { DBRef, isDBRefLike } from './db_ref';
 import { Decimal128 } from './decimal128';
@@ -358,7 +359,7 @@ function serializeDocument(doc: any, options: EJSONSerializeOptions) {
     doc != null &&
     typeof doc === 'object' &&
     typeof doc._bsontype === 'string' &&
-    doc[Symbol.for('@@mdb.bson.version')] !== BSON_MAJOR_VERSION
+    doc[BSON_VERSION_SYMBOL] !== BSON_MAJOR_VERSION
   ) {
     throw new BSONVersionError();
   } else if (isBSONType(doc)) {

src/parser/calculate_size.ts

@@ -81,7 +81,7 @@ function calculateElement(
       if (
         value != null &&
         typeof value._bsontype === 'string' &&
-        value[Symbol.for('@@mdb.bson.version')] !== constants.BSON_MAJOR_VERSION
+        value[constants.BSON_VERSION_SYMBOL] !== constants.BSON_MAJOR_VERSION
       ) {
         throw new BSONVersionError();
       } else if (value == null || value._bsontype === 'MinKey' || value._bsontype === 'MaxKey') {