Mongo object to array

mongo.object-to-array.js

// Untuk collection disesuaikan antara comics_id, comics_en, atau comics_contest
// sebaiknya dieksekusi sebelum jumlah like banyak (estimasi 1000)
// takutnya kehabisan memory
// @referensi: https://stackoverflow.com/questions/36164746/mongo-convert-embedded-document-to-array

db.books.aggregate([
	{"$unwind": "$sections"},
	{"$match": {
		"sections.likes": {
			$exists: true,
		},
	}},
	{"$project": {
	  "_id": true,
		"alias": true,
		"sections._id": true,
		"sections.alias": true,
		"sections.likes": true,
		"sections._like_type": {
			$type: "$sections.likes"
		},
		
	}},
	{"$match": {
		"sections._like_type": "object"
	}},
	
]).forEach(function(document){
  
	var idBook = document._id;
	var idSection = document.sections._id;
	var dumpLikes = [];
	
	
	var likes = document.sections.likes;
	
	for(a in likes) {
		dumpLikes.push(likes[a]);
	}
	
	// Jangan lupa ini juga diganti collection-nya
	db.books.updateOne({
		'_id': idBook,
		"sections._id": idSection
	}, {
		$set: {
			"sections.$.likes": dumpLikes
		}
	});
	

	// kosongin dulu untuk digunakan di iterasi berikutnya
	dumpLikes = [];
});