refactor: remove unnecessary async iterator checks

[vkarpov15]

Summary

Good point by @hasezoey in #15430: if (Symbol.asyncIterator != null) checks are no longer necessary because Symbol.asyncIterator was introduced in node 10.x, and Mongoose 9 requires Node >= 18 currently (may change before we formally release Mongoose 9).

Examples

[Copilot]

Pull Request Overview

This PR removes legacy checks for Symbol.asyncIterator in Query and Aggregate prototypes, since Mongoose 9 requires Node.js ≥18 and async iteration support is guaranteed.

• Drop conditional wrappers around async iterator definitions in both query.js and aggregate.js
• Remove outdated comments about enabling async iteration in older Node versions

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
lib/query.js	Always define Query.prototype[Symbol.asyncIterator] and cleaned up legacy comments
lib/aggregate.js	Always define Aggregate.prototype[Symbol.asyncIterator] and cleaned up legacy comments

Comments suppressed due to low confidence (3)

lib/query.js:5414

• Consider updating the TypeScript type definitions to reflect that Query now always implements [Symbol.asyncIterator], ensuring consistency for TypeScript consumers.

Query.prototype[Symbol.asyncIterator] = function queryAsyncIterator() {

lib/aggregate.js:1148

• Consider updating the TypeScript type definitions to reflect that Aggregate now always implements [Symbol.asyncIterator], ensuring consistency for TypeScript consumers.

Aggregate.prototype[Symbol.asyncIterator] = function() {

lib/query.js:5414

• No new tests were added to verify the always-available async iterator behavior on Query and Aggregate. Consider adding unit tests to cover async iteration.

Query.prototype[Symbol.asyncIterator] = function queryAsyncIterator() {

[AbdelrahmanHafez]

Nice!