deleteMany doesn' work

[LucVidal360]

Problem

It seems deleteMany never deletes anything.
Indeed, it's algorithm is:

• fetch all documents matching the query with a cursor
• extract their ids
• remove the documents in the collection with these ids.

Unfortunately

• the ids are compared using lodash.includes which uses SameValueZero:

  mongo-mock/lib/collection.js

  Line 132 in 80fdc61

  _.remove(state.documents || [], document => _.includes(idsToRemove, document._id));

• but the cursor returns cloned documents:

  mongo-mock/lib/cursor.js

  Line 52 in 80fdc61

  docs = _.cloneDeepWith(docs, cloneObjectIDs);

  • with cloned ObjectIds:

    mongo-mock/lib/cursor.js

    Lines 256 to 258 in 80fdc61

    	function cloneObjectIDs(value) {
    	return value instanceof ObjectId? ObjectId(value) : undefined;
    	}

This means ids never match (because they are not the same instance of ObjectIds), and nothing is ever deleted.

Possible fix

A solution could be to add a secret option to cursor to avoid cloning documents. To use only with deleteMany.